Veto q&a 7 Month22 (1)

@hang out
2018
May
Q
Relative speed = 120+80=200 km/hr
5 500
= 200 × = /
18 9 m s
(the two trains are moving in opposite direction)
Total distance = 100+150 = 250m
Total distance 250 250 × 9
Time =
= = = 4.5sec
Relative Speed 500 500
9
A merchant sells two dolls of price respectively
Rs.100 and Rs.150 with a profit of 30% on first
and loss of 30% on second. What is his net profit
/loss?
Selling price of first doll
⎛ 30 ⎞
= 100 + ⎜100 × ⎟= 100 + 30 = 130
⎝ 100 ⎠
Selling price of second doll
⎛ 30 ⎞
= 150 − ⎜150 × ⎟= 150 − 45 = 105
⎝ 100 ⎠
∴Total selling price = 130+105 = 235
Total cost price = 100+150 = 250
Net loss 250 − 235 15
= x100 = x100
250 250
= 6% loss
Q The price of a Scooter and TV are in the ratio 7:5
scooter costs Rs.8000 more than TV set, then price
of TV set is?
Let the prices be 7x and 5x
Price of scooter, 7x = 5x + 8000
(7x-5x=2x) 2x = 8000; x = 4000
∴Price of TV = 4000x5 = 20000
Q
Find the value of x, if
3( x −2) 5(2 −x)
=
5 3
3x
−6 10 −5x
=
5 3
3(3x-6) = 5(10-5x)
9x-18 = 50-25x
9x+25x =68
34x = 68
68
34
x= = 2
Q&A Bonus
3( x −2) 5(2 −x)
=
5 3
Q
Q Find (125+95) 2 - 4x125x95 ?
Given equation is in the form
(a+b) 2 - 4ab
ie = a 2 +2ab+b 2 -4ab
=a 2 -2ab+b 2 = (a-b) 2
(125-95) 2 = 30 2 = 900
Q The difference between 72% and 54% of a number
is 432. What is 55% of that number?
Let the number be ‘x’
72x
54x
∴ − = 432
100 100
18x
= 432
100
18x = 43200
43200
x = =2400
18
Q
y − x 3 = Find y:x
x 8
y − x 3 =
x 8
8(y-x) = 3x
8y-8x = 3x
8y-8x-3x=0
8y-11x=0
8y = 11x
8y
= 11
x
y 11
= ; y:x=11:8
x 8
The number is 2400
55
55% of 2400 =2400 x 100 =1320
A cylinder of radius 4cm and height 10 cm is melted
and recasted into a sphere of radius 2cm. How
many such sphere are got?
Radius of cylinder, r = 4cm
Height, h = 10cm
Volume of cylinder = πr 2 h = πx4 2 x10 = 160π
Radius of sphere = 2cm
4 3 4 3 32
Volume Area of sphere =
=π r = π x 2 = π
3 3 3
The 100 th Space Mission of ISRO - PSlV c-21
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