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StudyPin past Jamb questions and answers - Mathematics<br />

Question 1<br />

Find the value of 1101112 + 101002<br />

A. 11010112<br />

B. 1001012<br />

C. 10010112<br />

D. 10011112<br />

Answer C<br />

Solution:<br />

1101112<br />

+101002<br />

10010112<br />

Question 2<br />

A woman bought a grinder of N60,000. She sold it as loss 15%. How much<br />

did she sell it?<br />

A. N53,000<br />

B. N52,000<br />

C. N51,000<br />

D. N50,000<br />

Answer C<br />

Solution:<br />

Selling price, SP = Ny<br />

Cost price CP = N60,000<br />

Percentage loss = 15%<br />

Percentage =<br />

CP− SP<br />

CP<br />

x 100%<br />

15% = 60000−y<br />

x 100%<br />

60000<br />

15 (60000) = (60000 – y) 100<br />

60000-y =<br />

15 x 60000<br />

100<br />

60000-y = 9000<br />

y=60000 – 9000<br />

y= N51, 000<br />

Study Pin Jamb solution | Mathematics | www.studypin.com | 1


Question 3<br />

Express the product of 0.00043 and 2000 in standard form.<br />

A. 8.6 x 10 -3<br />

B. 8.3 x 10 -2<br />

C. 8.6 x 10 -1<br />

D. 8.6 x 10<br />

Answer C<br />

Solution:<br />

0.00043 = 43 x 10 -5<br />

2000 = 2x10 3<br />

Product = 43 x 10 -5 x 2 x 10 3<br />

= 86 x 10 -5+3<br />

= 86 x 10 -2 = 0.86<br />

= 8.6 x 10 -1<br />

See NCM 1 page 47 – 48<br />

Question 5<br />

A man donates 10% for his monthly net earnings to church. If it amounts to<br />

N4,500, what is his net monthly income?<br />

A. N40500<br />

B. N45000<br />

C. N52500<br />

D. N62000<br />

Answer B<br />

Solution:<br />

Amount given to church =<br />

N 4500 = 10<br />

100<br />

x monthly income<br />

Percentage of amount<br />

100%<br />

x monthly income<br />

Monthly income =<br />

N4500 x 100<br />

100<br />

= N45000<br />

Question 5<br />

If log 7.5 = 0.8751, evaluate 2 log 75 + log 750<br />

A. 6.6252<br />

B. 6.6253<br />

C. 66.252<br />

D. 66.253<br />

Answer B<br />

Solution:<br />

Study Pin Jamb solution | Mathematics | www.studypin.com | 2


Log 7.5 = 0.8751<br />

But 2Log 75 + log 750<br />

2log 7.5x10 + log 7.5 x 100<br />

2(log7.5 + log10) + Log 7.5 + Log100<br />

2(0.8751 + 1) + 0.8751 + 2<br />

2 x 1.8751 + 2.8751<br />

2.7502 + 2.8751<br />

=> 6.6253<br />

See comprehensive maths page 215<br />

Question 6<br />

Solve for x in n 8x-2 = 2/25<br />

A. 4<br />

B. 6<br />

C. 8<br />

D. 10<br />

Answer D<br />

Solution:<br />

8x -2 = 2/25<br />

Divide by 81<br />

x -2 =<br />

2<br />

= 1<br />

8 x 25 4 x 25<br />

x -2 = 1<br />

100 = 1 x 2 = 1<br />

100<br />

Taking reciprocal<br />

x 2 = 100<br />

x = √100 = 10<br />

Question 7<br />

Simplify 2√2−√3<br />

√2+ √3<br />

A. 3√6 − 7<br />

B. 3√6 + 7<br />

C. 3√6 − 1<br />

D. 3√6 + 1<br />

Answer A<br />

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Solution:<br />

Simplify 2√2−√3<br />

√2+ √3<br />

Taking the conjugate of<br />

√2 + √3 = √2 - √3<br />

Then, multiply the denominator and numerator by he conjugate<br />

2√2−√3<br />

√2+ √3 x 2√2−√3<br />

√2− √3<br />

⇒<br />

2√2 x √2 −2√2 x √3 x √2+ √32<br />

√2 2 + √2 x √3 + √2 x √3− √2 2<br />

4 − 2√6 − √6 + 3<br />

2 − √6 + √6 − 3<br />

7 − 3√6<br />

−1<br />

?<br />

−1 − 3√6<br />

−1<br />

⇒ 3√6 – 7<br />

Reference: Comprehensive <strong>Maths</strong> page 30<br />

Question 8<br />

Evaluate Log 28 + log216 - log24<br />

Answer C<br />

Solution:<br />

Log 28 + log216 - log24<br />

Log22 3 + log 22 4 – log2 2 2<br />

3log2 2 + 4log2 2 – 2log2 2<br />

But log2 2 = 1<br />

3 + 4 – 2 = 5<br />

Question 9<br />

P = {1, 2, 3, 4, 5} and P ∩ Q = {1, 2, 3, 4, 5, 6, 7}, list the element in Q<br />

A. {6}<br />

B. {7}<br />

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C. {6,7}<br />

D. {5,6}<br />

Answer C<br />

Solution:<br />

P = {1, 2, 3, 4, 5}<br />

PuQ = {1, 2, 3, 4, 5, 6, 7}<br />

∴ P+Q = PuQ<br />

Q = PuQ – P<br />

= {6, 7}<br />

Comprehensive <strong>Maths</strong> page 49<br />

Question 10<br />

From the vein diagram below, the shaded parts represents<br />

A. (P ∩ Q) ∪ (P ∩ R)<br />

B. (P ∪ Q) ∩ (P ∪ R)<br />

C. (P ∪ Q) ∪ (PER)<br />

D. (P ∩ Q) ∩ (P ∩ R)<br />

Answer D<br />

Solution:<br />

P<br />

Q<br />

R<br />

Consider the shaded portion:<br />

First PnQ then, PnR<br />

Again PnQnR<br />

∴ (PnQ) n (PnR)<br />

Question 11<br />

gt 2 – K – w = 0, make g the subject of the formular.<br />

A. K+w<br />

t 2<br />

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B. K−w<br />

t 2<br />

C. K+w<br />

t<br />

D. K−w<br />

t<br />

Answer A<br />

Solution:<br />

gt 2 – K – w = 0<br />

gt 2 = k+ w<br />

g =<br />

k+ w<br />

t 2<br />

See NCM page 50 – 51<br />

Question 12<br />

Factorize 2y 2 – 15xy + 18x2<br />

A. (2y – 3x)(y - 6x)<br />

B. (3y – 2x) (y – 6x)<br />

C. (2y – 3x) (y - 6x)<br />

D. (2y - 3x) (y - 6x)<br />

Answer B<br />

Solution:<br />

2y2 – 15xy + 18x2<br />

Product = 2 x 18 = 36<br />

Sum = - 15<br />

Factors of 36 and -15 are – 12 and -3<br />

∴ Fractioning<br />

2y 2 – 12xy – 3xy + 18x 2<br />

2y (y – 6x) -3x (y – 6x)<br />

(2y – 3x)(y - 6x)<br />

See comprehensive maths page 61<br />

Question 13<br />

Find the value of k if y-1 is factor of y 3 + 4y 2 + ky – 6<br />

A. -6<br />

B. -4<br />

C. 0<br />

D. 1<br />

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Answer D<br />

Solution:<br />

f(y) = y 3 + 4y 2 + ky – 6<br />

For y - 1 to be a factor then,<br />

y – 1 = 0, y=1<br />

Substitute y=1 into f(y) =0<br />

f(1) = 1 3 + 4(1) 2 ⦤ (1) – 6 = 0<br />

1 + 4 x 1 + k – 6 = 0<br />

1 + 4 + k – 6 = 0<br />

K =1<br />

Question 13<br />

y varies directly as w2. When y=8, w=2, find y when w = 3<br />

A. 18<br />

B. 12<br />

C. 9<br />

D. 6<br />

Answer A<br />

Solution:<br />

y⋉ w 2<br />

y = kw 2 (k= constant of variation)<br />

when y = 8, w = 2<br />

8 = K x 2 2 = k= 4<br />

K = 8/4 = 2<br />

∴ y = 2w 2<br />

When w = 3<br />

y = 2 x 3 2 = 2 x 9 = 18<br />

Question 15<br />

P varies directly as Q and inversely as R. When Q = 36 and R = 16, P27. Find<br />

the relationship between P,Q AND R.<br />

Q<br />

A.<br />

12R<br />

B. 12Q<br />

R<br />

C. 12QR<br />

D. 12/QR<br />

Answer B<br />

Solution:<br />

P⋉Q, P⋉ 1 R<br />

∴ P⋉ Q/R (K = constant)<br />

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When Q = 36, R = 16, P = 27<br />

K x 36<br />

27 =<br />

16<br />

K x 36 = 27 x 16<br />

K = 27x16<br />

36<br />

K = 12<br />

∴ P = 12Q<br />

R<br />

Question 16<br />

Evaluate the inequality<br />

x<br />

2 + 3 4 ≤ 5x 6 − 7 12<br />

A. x ≥ 4<br />

B. x ≤ 3<br />

C. x ≥ −3<br />

D. x ≤ −4<br />

Answer A<br />

Solution:<br />

x<br />

2 + 3 4 ≤ 5x 6 − 7 12<br />

x<br />

2 − 5x 6 ≤ − 7 12 − 3 4<br />

3x − 5x<br />

6<br />

≤ − −7 − 9<br />

12<br />

−2x<br />

6<br />

≤ −16<br />

12<br />

−x<br />

3 ≤ −4<br />

3<br />

Cancel the denominator<br />

−x ≤ −4<br />

x ≥ −4<br />

−1<br />

= x ≥ 4<br />

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Comprehensive maths Page 56<br />

Question 17<br />

The nth term of anA.P. is 13 while the 10 th term is 31. Find the 24 th term.<br />

A. 89<br />

B. 75<br />

C. 73<br />

D. 69<br />

Answer C<br />

Solution:<br />

4 th term, T4 = 13<br />

10 th term, T10 = 31<br />

Using Tn = a + (n-1) d<br />

When a= first term<br />

d = common difference<br />

T4 = a + (4 – 1)d = 13 _______(1)<br />

T10 = a + (10-1) = 31 _______(2)<br />

a + 3d = 13 ________(3)<br />

a + 9d = 31 _________(4)<br />

(4) – (3)<br />

a – a + 9d – 3d = 31 – 13<br />

6d = 18<br />

d = 18/6 = 3<br />

Substitute d = 3 into (3)<br />

a + 3d = 13<br />

a + 3 x 3 = 13<br />

a = 13 – 9 = 4<br />

The T2 = a + (n-1)d<br />

T24 = 4 + 23 x 2<br />

= 4 + 23 x 2<br />

= 4 69 = 73<br />

Question 18<br />

What is the common ratio of the G.P. (√10 + √5) + (√10 + 2√5)+ ...?<br />

A. √2<br />

B. √5<br />

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C. 3<br />

D. 5<br />

Answer A<br />

Solution:<br />

Common ratio<br />

r =<br />

√10 +2√5<br />

√10+ √5<br />

=<br />

=<br />

Second term<br />

first term<br />

Third term<br />

Fourth term<br />

or<br />

Taking conjugate of √10 + √5<br />

= √10 - √5<br />

∴ r =<br />

√10 +2√5<br />

√10+ √5<br />

x<br />

√10 −2√5<br />

√10− √5<br />

r = √102 − √50 + 2√50−2 √5 x √5<br />

√10 2 − √50 + √50 − √5 2<br />

r =<br />

r =<br />

10+ √50 −10<br />

10−5<br />

√25 x √2<br />

5<br />

= 5√2<br />

5<br />

= r = √50<br />

5<br />

r = √2<br />

See comprehensive maths page 100, 30<br />

Question 19<br />

A binary operation * is defined by x*y= x y . if x*2=12-x, find the possible<br />

value of x.<br />

A. 3,4<br />

B. 3,-4<br />

C. -3,4<br />

D. -3,-4<br />

Answer B<br />

Solution:<br />

X × Y = x y<br />

X × 2 = 12 – x<br />

Compare x × y to x × 2<br />

∴ x × 2 = x 2<br />

Study Pin Jamb solution | Mathematics | www.studypin.com | 10


x 2 = 12 = x<br />

x 2 + x − 12 = 0<br />

x 2 + 4x − 3x − 12 = 0<br />

x(x + 4) -3 (x + 4) = 0<br />

(x – 3)(x +4)<br />

= x- 3 = 0 or x + 4 = 0<br />

x = 3 or x = -4<br />

Question 20<br />

Find y, if ( 5<br />

−6<br />

2 7 ) (x y ) =( 7<br />

A. 8<br />

B. 5<br />

C. 3<br />

D. 2<br />

Answer C<br />

Solution:<br />

( 5 −6<br />

2 7 ) (x y ) =( 7<br />

−11 )<br />

It becomes<br />

5x – 6y = 7_______(1) x2<br />

2x – 7y = -11_____(2) x5<br />

−11 )<br />

10x – 12y = 14 ____(3)<br />

10x – 35y = -55____(4)<br />

(4) – (3)<br />

10x – 10x -35y – (-12y) = -55-14<br />

-35y + 12y = -69<br />

-23y = -69<br />

y = 69/23 = 3<br />

Question 21<br />

−x 12<br />

If | | = -12 find x.<br />

−1 4<br />

A. -6<br />

B. -2<br />

C. 3<br />

D. 6<br />

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Answer A<br />

Solution:<br />

−x 12<br />

|<br />

−1 4 | = -12<br />

−x × 4 − (−1 × 12) = −12<br />

−4x + 12 = −12<br />

−4x = −12 − 12<br />

−4x = −24<br />

x = −24/4<br />

x = −6<br />

Question 22<br />

Fin the value of<br />

A. 12<br />

B. 10<br />

C. -1<br />

D. -2<br />

Answer D<br />

Solution:<br />

0 3<br />

1 7<br />

0 5<br />

2<br />

8<br />

4<br />

0 3<br />

1 7<br />

0 5<br />

2<br />

8<br />

4<br />

Bringing the determinant method<br />

0 | 7 8 8 7<br />

| -3 |1 | +2 |1<br />

5 4 0 4 0 5 |<br />

0(7 × 4 − 5 × 8) − 3 (1 × 4 − 0 × 8) + 2 (1 × 5 − 0 × 7)<br />

0 × −12 − 3 × 4 + 2 × 5<br />

0 − 12 + 10 = −2<br />

Question 23<br />

How many side has a regular polygon whose interior angle is 135° each?<br />

A. 12<br />

B. 10<br />

C. 9<br />

D. 8<br />

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Answer D<br />

Solution:<br />

Interior angle = 135<br />

Exterior angle 180-interior angle<br />

Exterior angle = 180 – 135<br />

= 45°<br />

∴ Number of sides (n)<br />

n = 360<br />

exterior = 360<br />

45 = 8<br />

Comprehensive maths page 140<br />

Question 24<br />

In the figure below, KL//NM, LN bisects


Question 25<br />

q 30<br />

P+2q<br />

From the figure above, what is the value of p?<br />

A. 135°<br />

B. 90°<br />

C. 60°<br />

D. 45°<br />

Answer B<br />

Solution:<br />

q=30° (Vertically opposite angels)<br />

∴ P + 2q = P+ 2 x 30 = P + 60<br />

P + 2q + 30 = 180 (sum of angles on a straight line)<br />

P + 60 + 30 = 180<br />

P = 180 – 60 – 30 = 90<br />

Comprehensive page 125<br />

Question 26<br />

Find the value of x in the figure above.<br />

A. 20√3cm<br />

B. 10√3cm<br />

C. 5√3cm<br />

D. 5√3cm<br />

Answer B<br />

Solution:<br />

30°<br />

60°<br />

Since the angles and one side is given, x can be found using sine rule.<br />

x<br />

sin60 = 10<br />

sin30<br />

Cross multiply<br />

xsin30 = 10sin60<br />

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x = 10sin60<br />

sin30<br />

x = 10 × √3<br />

2 = 5√3<br />

1<br />

2<br />

x = 5√3<br />

1 × 2 1<br />

x = 10√3cm<br />

Question 27<br />

If the angle of a sector of a circle with radius 10.5cm is 120°, find the<br />

perimeter of the sector.<br />

A. 40cm<br />

B. 43cm<br />

C. 45cm<br />

D. 48cm<br />

Answer B<br />

Solution:<br />

r = 10.5cm, angle ϴ=120°<br />

Perimeter of a sector<br />

= 2r + ϴ/360 × 2πr<br />

2 × 10.5 + 120<br />

360 × 22 7 × 10.5<br />

21 + 1 3 × 2 × 22 7 × 10.5<br />

= 21 + 22 = 43cm<br />

Question 28<br />

A cylindrical tank has a capacity of 6160m3. What is the depth of the tank if<br />

the radius of its base is 28cm?<br />

A. 8.0m<br />

B. 7.5m<br />

C. 5.0m<br />

D. 2.5m<br />

Answer D<br />

Solution:<br />

Capacity = Volume of tank (v)<br />

v = 6160cm 3<br />

Radius, r =28cm<br />

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V = πr 2 h<br />

6160 x 7 = 22 x 28h<br />

h = 6160 × 7<br />

22 × 28<br />

h = 2.5m<br />

Question 29<br />

The locus of a dog tethered to a pole with a rope of 4m is<br />

A. Circle with diameter 4m<br />

B. Circle with radius 4m<br />

C. Semi-circle with diameter 4m<br />

D. Semi-circle with radius 4m<br />

Answer B<br />

Solution:<br />

The locus of a point to a pole with a rope of 4m is a circle of radius 4m<br />

Question 30<br />

Find the mid-point of S(-5,4) and T(-3-2)<br />

A. -4,2<br />

B. 4,-2<br />

C. -4, 1<br />

D. 41 -1<br />

Answer C<br />

Solution:<br />

(x1, y1) = (-5, 4), (x2, y2) = (-3, -2)<br />

∴ mid − point (x, y)<br />

x = x 1+x 2<br />

2<br />

=<br />

x = −5 − 3<br />

2<br />

y = y 1+y 2<br />

2<br />

−5+ −3<br />

2<br />

= −8<br />

2 = −4<br />

= 4+−2<br />

2<br />

∴ (x, y) = (−4,1)<br />

= 4−2<br />

2 = 2 2 = 1<br />

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Question 31<br />

The gradient of the line joining (x,3) and (1,2) is ½. Find the value of x.<br />

A. 5<br />

B. 3<br />

C. -3<br />

D. -5<br />

Answer A<br />

Solution:<br />

Gradient (m) = ½<br />

(x 1 y 2 ) = (x 1 4), (x 2 y 2 ) = (1,2)<br />

M = (y 2y 1 )<br />

= −2<br />

(x 2 x 1 ) 1−x<br />

1<br />

2 = 2 − 4<br />

1 − x = −2<br />

1 − x<br />

1(1 − x) = 2x − 2<br />

1 − x = −4<br />

x = 1 + 4 = +5<br />

Question 32<br />

In the figure below, what is the equation of the line that passes the y-axis at<br />

(0,5) and passes the x-axis at (5,0)?<br />

A. y=x+5<br />

B. y=-x+5<br />

C. y=x-5<br />

D. y=-x-5<br />

Answer B<br />

Solution:<br />

x 1 y 1 = (0, 5), (x 2 , y 2 ) = (5, 0)<br />

From equation of a line through two points<br />

y − y 1<br />

x − x 1<br />

= y 2 − y 1<br />

x 2 − x 1<br />

y − 5<br />

x − 0 = 0 − 5<br />

5 − 0<br />

5<br />

4<br />

3<br />

2<br />

1<br />

6 5 4 3 2 1 1 2 3 4 5<br />

1<br />

2<br />

3<br />

4<br />

5<br />

y − 5<br />

x<br />

= −5<br />

5<br />

5y – 25 = −5x<br />

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Divided through h by 5<br />

y − 5 = −x<br />

y = −x + 5<br />

NCM 2 page 69<br />

Question 33<br />

Calculate the mid point of the line segment y-4x+3=0 which lies between<br />

the x-axis and y-axis.<br />

A. ( 3 −3<br />

8 2 )<br />

B. ( 3 3<br />

8 2 )<br />

C. ( −2 2<br />

2 2 )<br />

D. ( −2 3<br />

3 2 )<br />

Answer A<br />

Solution:<br />

Mid-point of a line segment y − 4x + 3 = 0<br />

When y = 0<br />

0 – 4x = -3<br />

-4x = -3<br />

x= −3 ⁄<br />

−4<br />

= 3 4<br />

∴ (x 1 y 1 ) = ( 3 ⁄ 4,<br />

0)<br />

When x=0<br />

y-4 (0) + 3= 0<br />

y=-3<br />

(x 2 y 2 ) = (0, -3)<br />

∴mid-point coordinates (x, y)<br />

x = x 1+x 2<br />

2<br />

= 3⁄ 4 +0<br />

2<br />

= 3/8<br />

y = y 1 + y 2<br />

2<br />

= 0 ± 3<br />

2<br />

= −3<br />

2<br />

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(x, y) = (3/4, −3/2)<br />

Question 34<br />

Find the equation of straight line through (-2, 3) and perpendicular to<br />

4x+3y-5=0<br />

A. 3x - 4y + 18 = 0<br />

B. 3x + 2y - 8=0<br />

C. 4x + 5y + 3=0<br />

D. 5x - 2y - 11=0<br />

Answer C<br />

Solution:<br />

(x, y) = (−2, 3)<br />

Equation of line perpendicular to 4x + 3y – 5 = 0<br />

Gradient of line, m<br />

4x + 3y -5 = 0<br />

y + 4.3 x − 5/3<br />

Perpendicularity, m1 m2 = -1<br />

m2 = -1/m1 = −1<br />

4 = ⁄ (3)<br />

3 4<br />

Using equation<br />

y = mx + c<br />

y = 3 4 x<br />

4y = 3x<br />

3x − 4y = C<br />

For (x, y) = (-2, 3)<br />

3(-2) – 4(3) = c<br />

-6 – 12 = c<br />

C = -18<br />

Substituting c = -18<br />

3x – 4y = c = −18<br />

Question 35<br />

Find the value of 1+cosθ<br />

A. 25/13<br />

B. 18/13<br />

C. 8/13<br />

D. 5/13<br />

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Answer B<br />

Solution:<br />

sinϴ = 12/13<br />

12<br />

13<br />

Using Pythagoras rule<br />

13 2 =12 2 +x 2<br />

x 2 -13 2 – 12 2 = 169 – 144<br />

x 2 = 25<br />

x = √25 =5<br />

x<br />

ϴ<br />

∴ + cosϴ = 1 + x 13 = 1 1 + 5 13<br />

= 13 + 5/13<br />

= 18<br />

13<br />

Question 37<br />

Find the minimum value of y = x 2 − 2x – 2<br />

A. 4<br />

B. 1<br />

C. -1<br />

D. -4<br />

Answer D<br />

Solution:<br />

y = x 2 − 2x – 2<br />

dy<br />

dx = 2x − 2<br />

At minimum point<br />

dy<br />

dx = 0<br />

2x= 2<br />

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x = 2 2 = 1<br />

Substitution into (1)<br />

y=1 2 -2 (1) – 3<br />

y=1-2-3 = -4<br />

Question 38<br />

Evaluate ∫ sin2 dx<br />

A. Cos2x+k<br />

B. 1/2cos 2x + k<br />

C. -1/2cos 2x + k<br />

D. –cos 2x + k<br />

Answer C<br />

Solution:<br />

∫ sin2xdx = 1 (−cos2x) + k<br />

2<br />

= 1 2<br />

cos2x + k<br />

Question 39<br />

Evaluate ∫(2x + 3) 1⁄ 2 dx<br />

A. 1/12(2x+3) 6 + k<br />

B. 1/3(2x+3) 1/2 +k<br />

C. 1/3 (2x +3) 3/2 + k<br />

D. 1/12(2x + 3) 1/4 +k<br />

Answer C<br />

Solution:<br />

∫(2x + 3) 1⁄ 2 dx<br />

Let u = 2x+3<br />

dy<br />

dx = 2, dx = du 2<br />

∴ ∫ u du = 1 2 u<br />

∫ u 1⁄ 2 × 1 2 du = 1 2 ∫ u1 ⁄ 2du<br />

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1<br />

2 u1 ⁄ 2 × 2 3 + k<br />

1<br />

3 u1 ⁄ 2 + k<br />

1<br />

3 (2x + 3)3 ⁄ 2 + k<br />

Question 40<br />

The pie chart above shows the monthly distribution of a man’s salary on<br />

food items. If he spent N8,000 on rice, how much did he spend on yam?<br />

A. N24,000<br />

B. N18,000<br />

C. N16,000<br />

D. N12,000<br />

Answer C<br />

Solution:<br />

Sectorial angle for yam<br />

=360 – (70 + 800+ 50)°<br />

=360 – 200 = 160°<br />

Rice = 80/360 x total amount(T)<br />

= 80<br />

360 × T<br />

800 = 80<br />

360 × T<br />

T =<br />

360 ×8000<br />

80<br />

T = N36,000<br />

Amount on yam = 160<br />

360° × 16000<br />

N16000<br />

Question 41<br />

The mean of 2-t, 4+t 3-2t and t-1 is<br />

A. t<br />

B. –t<br />

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C. 2<br />

D. -2<br />

Answer C<br />

Solution:<br />

Mean x̅ =<br />

10<br />

5 = 2<br />

(2−7) + (4+t)+ (3−2t) + (2+t) + (t−1)<br />

5<br />

Question 42<br />

Values 0 1 2 3 4<br />

Frequency 1 2 2 1 9<br />

Find the mode of the distribution above.<br />

A. 1<br />

B. 2<br />

C. 3<br />

D. 4<br />

Answer D<br />

Solution:<br />

From the table, mode is the value with the highest frequency<br />

∴ i.e. =4<br />

Comprehensive mathematics page 244<br />

Question 43<br />

Find the median of 5,9,1,10,3,8,9,2,4,5,5,5,7,3 and 6.<br />

A. 6<br />

B. 5<br />

C. 4<br />

D. 3<br />

Answer B<br />

Solution:<br />

Rearranging in order of increasing magnitude<br />

1, 2, 3, 3, 4, 5, 5, 5, 5, 6, 7, 8, 9, 9, 10<br />

100k out for the middle number by calculating left and right<br />

Hence median = 5<br />

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Question 44<br />

Calculate the standard deviation of 5,4,3,4 and 1<br />

A. √2<br />

B. √3<br />

C. √6<br />

D. √10<br />

Answer A<br />

Solution:<br />

Mean x̅ = 5+4+3+4+1<br />

5<br />

15<br />

15 = 3<br />

x d=x-x̅ d 2<br />

5 2 4<br />

4 1 1<br />

3 0 0<br />

2 -1 1<br />

1 -2 4<br />

∑ d 2 = 10<br />

Standard deviation = √ ∑ d2<br />

= √ 10 5 = √2<br />

n<br />

See comprehensive mathematics page 252<br />

Question 45<br />

In how many ways can a team of 3 girls be selected from 7 girls?<br />

A. 7!/3!<br />

B. 7!/4!<br />

C. 7!/4!3!<br />

D. 7!/2!5!<br />

Answer C<br />

Solution:<br />

Selection is a combination<br />

n Cr =<br />

n!<br />

(n−r)!r!<br />

n = 7 r= 3<br />

7 C3= 7!<br />

(7−3)!3! = 7!<br />

4!3!<br />

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7 C3= 7!<br />

4!3! ways<br />

Question 46<br />

Number 1 2 3 4 5 6<br />

Frequency 18 22 20 16 10 14<br />

The table above represents the outcome of throwing a die 100time. What is<br />

the probability of obtaining at least 4?<br />

A. 1/5<br />

B. ½<br />

C. 2/5<br />

D. 3/4<br />

Answer C<br />

Solution:<br />

At least 4 = 4, 5, 6<br />

Total frequency for, 4, 5, 6<br />

= 16 + 10 + 14 = 40<br />

∴ P (at least 4) =<br />

At leat 4<br />

Total frequency<br />

= 40<br />

100 = 2 5<br />

Comprehensive mathematics page 218<br />

Question 47<br />

A number is chosen at random from 10 to 30 both inclusive, what is the<br />

probability that the number is divisible by 3?<br />

A. 2/15<br />

B. 1/10<br />

C. 1/3<br />

D. 2/5<br />

Answer<br />

Solution:<br />

10 – 30 inclusive<br />

= {10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,<br />

30}<br />

Divisible by 3= {12, 15, 18, 21, 21, 24, 27, 30}<br />

Total number = 21<br />

∴ P (divisible by 3) = 7 21 = 1/3<br />

See comprehensive page 218 - 220<br />

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