ratio and proportion Model Questions & Answers, Practice Test for ssc steno grade c d 2024

Answer: (c)

Out of 10 litre of solution, there is 1 litres of nitric acid and 9 litres of water.

Let x litres of water be added to the solution so that the diluted solution is of 4% strength.

∴ 4% of (10 + x) = 1⇒x = 15.

Answer: (a)

Here, S.P. of mixture = C. P. of pure milk = Rs 3 per litre

Now, S. P. of mixture = ${100 + 20}/{100}$ × C.P. of mixture

⇒C.P. of mixture = ${3 × 100}/{120}$ = Rs 2.5 per litre

Also, C. P of water = Rs 0

By the rule of alligation :

∴ Ratio of pure milk and water in mixture = ${2.5}/{0.5}$ = 5:1

For five litres of water, quantity of pure milk

= 5 × 5 = 25 litres

Answer: (d)

Let the age of son and father is x and 3x years respectively 6 years hence.

∴ Present age of father = (3x – 6) years

Present age of son = (x – 6) years

3 years ago, age of father = 3x – 6 – 3

= (3x – 9) years

Age of son = x – 6 – 3 = (x – 9) years

According to given condition,

3x – 9 = 9(x – 9)⇒3x – 9 = 9x – 81

⇒81 – 9 = 9x – 3x⇒6x = 72

∴ x = ${72}/6$ = 12

∴ Present age of father = 3 × 12 – 6 = 30 years

Answer: (d)

${\text"Male"}/{\text"Total"} = {{1525 × 27}/{61} + {2600 × 6}/{13}}/{1525 + 2600} = {1875}/{4125} = 5/{11}$

∴ ${\text"Male"}/{\text"Female"} = 5/{11 - 5} = 5/6$

Answer: (b)

a : b = $3/2 : 9/4 and b : c = 2 : 7/2$

⇒a : b = 6 : 9 and b : c = 4 : 7

LCM of 9 and 4 = 36

⇒a : b = 24 : 36 and b : c = 36 : 63

∴ a : b : c = 24 : 36 : 63

⇒a : b : c = 8 : 12 : 21