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R<br />

13 Veto<br />

follow us: facebook.com/vetotrivandrum 14<br />

Work and Time<br />

type - i<br />

1. A can do a work in 6 days B can<br />

do the some work in 3 days. In<br />

howmany days working together<br />

they will finish the same work?<br />

(a) 3 days (b) 9 days<br />

(c) 2 days (d) None<br />

Ans: (c) 2 days<br />

A can do a work in x days<br />

B can do the same work in y days<br />

then A and B can do the work in<br />

xy<br />

x+<br />

y<br />

OR<br />

days<br />

A→ x days<br />

B→ y days<br />

A+B =<br />

Exp: x = 6<br />

y = 3<br />

6× 3 6×<br />

3<br />

= = 2days<br />

6+<br />

3 9<br />

2. A and B can seperately finish a<br />

work in 10 days and 15 days<br />

respectively. In how may days<br />

working together, they will finish<br />

the work?<br />

(a) 6 days<br />

(c) 9 days<br />

xy<br />

x+<br />

y<br />

Ans: (a) 6 days<br />

(b) 2 days<br />

(d) 3 days<br />

Exp: x = 10, y = 15<br />

xy 10× 15 10×<br />

15<br />

= = = 6 days<br />

x+ y 10 + 15 25<br />

type - iI<br />

3. A can do a work in 30 days.<br />

B can do the same work in 60<br />

days. C can do the same work<br />

in 80 days. A, B and C working<br />

together, in how many days they<br />

will finish the same work?<br />

(a) 9 days (b) 16 days<br />

(c) 10 days (d) None of these<br />

Ans: (b) 16 days<br />

hnPbIpamÀ imkvXmwtIm«<br />

A→ x days<br />

B → y days<br />

C → z days<br />

ü<br />

A+B+C =<br />

days<br />

xy + yz + xz<br />

Exp: x = 30, y = 60, z = 80<br />

xyz<br />

xy + yz + xz<br />

30× 60×<br />

80<br />

=<br />

30× 60 + 60× 80 + 30×<br />

80<br />

30× 60×<br />

80<br />

=<br />

1800 + 4800 + 2400<br />

30× 60×<br />

80<br />

= = 16 days<br />

9000<br />

4. A, B and C can do a work seperately<br />

in 10 days, 15 ays and 30<br />

days. In how many days working<br />

together they will finish the work?<br />

(a) 6 days<br />

(c) 4 days<br />

Ans: (b) 5 days<br />

(b) 5 days<br />

(d) 2 days<br />

Exp: x = 10, y = 15, z = 30<br />

xyz<br />

=<br />

xy + yz + xz<br />

10× 15×<br />

30<br />

=<br />

10× 15 + 15× 30 + 10×<br />

30<br />

10× 15×<br />

30<br />

=<br />

150 + 450 + 300<br />

10× 15×<br />

30<br />

= = 5 days<br />

900<br />

type - iII<br />

5. A and B together can complete a<br />

work in 12 days. If A alone can<br />

finish the same work in 18 days.<br />

In how many days B alone can<br />

finish the same work?<br />

(a) 18 days (b) 36 days<br />

(c) 72 days (d) None of these<br />

Ans: (b) 36 days<br />

A+B→ x days<br />

A → y days<br />

B→<br />

xy<br />

y−<br />

x<br />

days<br />

Exp: x = 12, y = 18<br />

xy<br />

y x<br />

12× 18 12×<br />

18<br />

= = = 36 days<br />

18 12 6<br />

6. A and B and C together can complete<br />

a work in 10 days. If B and<br />

C together alone can complete the<br />

same work in 15 days. In how<br />

many days A alone can complete<br />

the same work?<br />

(a) 15 days<br />

(c) 25 days<br />

Ans: (b) 30 days<br />

(b) 30 days<br />

(d) None of these<br />

Exp: x = 10, y = 15<br />

xy<br />

y x<br />

10× 15 10×<br />

15<br />

= = = 30 days<br />

15 10 5<br />

type - iV<br />

7. If 12 men can do a job in 16 days.<br />

In how many days 8 men can<br />

complete the work?<br />

(a) 12 days (b) 24 days<br />

(c) 30 days (d) None of these<br />

Ans: (b) 24 days<br />

12m<br />

→16days<br />

Exp :<br />

8 m → ?<br />

12×<br />

16<br />

= = 24 days<br />

8<br />

Short Cut<br />

Numerator = Multiply the 1 st row<br />

Denominator = 2 nd row<br />

8. 21 men can do a job in 10 days.<br />

In how many men can do finish<br />

the same work in 7 days?<br />

(a) 20 (b) 30<br />

(c) 15 (d) None of these<br />

Ans: (b) 30<br />

21m<br />

→10days<br />

Exp :<br />

? → 7days<br />

21×<br />

10<br />

= = 30 men<br />

7<br />

9. In a camp, there are 50 days food<br />

in 20 peoples. If 5 more peoples<br />

attend the camp. In how many<br />

days food are sufficient in the<br />

camp?<br />

(a) 30 days<br />

(c) 40 days<br />

Ans: (b) 30<br />

(b) 25 days<br />

(d) None of these<br />

5 more people attend the camp<br />

∴Total people = 20 + 5 = 25<br />

20 → 50days<br />

ü →<br />

20×<br />

50<br />

Exp : = 40 days<br />

25<br />

type - V<br />

10. 6 men or 8 women can do a job<br />

in 46 days. How long will 8 men<br />

and 20 women do the same job?<br />

(a) 10 days (b) 12 days<br />

(c) 6 days (d) None of these<br />

Ans: (b) 12 days<br />

6m or 8w → 46 days<br />

8m and 20 w → ?<br />

No. of days (or/and)<br />

6× 8× 46 6× 8×<br />

46<br />

= =<br />

6× 20 + 8× 8 120 + 64<br />

6× 8×<br />

46<br />

= = 12 days<br />

184<br />

Short-cut<br />

Multiply the 1st row (Numerator)<br />

Cross xied and added each other<br />

(denominator)<br />

11. 3 men or 4 women can do a job<br />

in 43 days. How long will 7 men<br />

and 5 women do the same job?<br />

(a) 12 days (b) 24 days<br />

(c) 48 days (d) 6 days<br />

Ans: (a) 12 days<br />

3m or 4w → 43 days<br />

=<br />

7m and 5 w → ?<br />

3× 4× 43 3× 4×<br />

43<br />

Exp : = = = 12 days<br />

15 + 28 43<br />

12. 8 men or 12 women can do a job<br />

in 18 days. How long will 18 men<br />

and 9 women do the same job?<br />

(a) 3 days (b) 6 days<br />

(c) 12 days (d) None of these<br />

Ans: (b) 6 days<br />

8m or 12w →18<br />

days<br />

18m and 9 w → ?<br />

8× 12× 18 8× 12×<br />

18<br />

Exp : ℵ<br />

72 + 216 288<br />

type - VI<br />

6days<br />

13. 1 men or 2 women or 3 boys<br />

do a piece of job in 44 days. In<br />

howmany days to finish the same<br />

piece of job done by 1 men and<br />

1 women and 1 boy?<br />

(a) 44 days (b) 24 days<br />

(c) 22 days (d) 12 days<br />

Ans: (b) 24 days<br />

1M or 2W or 3B → 44days<br />

Exp :<br />

1M and 1W and 1B → ?

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