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SSC CGL 2017 PYQ — Question 22

SSC CGL Tier II Quant - 12/01/2017 • Quantitative Aptitude • Q22

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There are three bottles of mixture of syrup and water of ratios 2:3, 3:4 and 7:5. 10 Litres of first and 21 Litres of second bottles are taken. How much quantity from third bottle is to be taken so that final mixture from three bottles will be of ratios 1:1.

Show answer & explanation

Correct answer: D

Explanation

The correct answer is Option 4 i.e. 30

Understanding

Application

Ratio of quantities of syrup and water in 1st bottle = 2 : 3

And

10 litres of 1st bottle is taken.

So,

Quantity of syrup taken from 1st bottle = 10 × 2/5 = 4 litres

And

Quantity of water taken from 1st bottle = 10 × 3/5 = 6 litres

Ratio of quantities of syrup and water in 2nd bottle = 3 : 4

And

21 litres of 2nd bottle is taken.

So,

Quantity of syrup taken from 2nd bottle = 21 × 3/7 = 9 litres

And

Quantity of water taken from 2nd bottle = 21 × 4/7 = 12 litres

Ratio of quantities of syrup and water in 3rd bottle = 7 : 5

And

Suppose x litres of 3rd bottle is taken.

So,

Quantity of syrup taken from 3rd bottle = x × 7/12 = 7x/12 litres

And

Quantity of water taken from 3rd bottle = x × 5/12 = 5x/12 litres

The ratio of syrup and water should be 1 : 1 when we mix the mixtures from 3 bottles.

So,

(4 + 9 + 7x/12) = (6 + 12 + 5x/12)

2x/12 = 5

x = 30

Hence, 30 litres from third bottle is to be taken.