Question

In a mixture of 156 litres, the ratio of milk and water is 7 : 6. How much water should be added to make the ratio 14 : 13?
1. 5 liters
2. 16 litres
3. 60 litres
4. 6 litres
5. 4 litres

Answer 1

Correct Answer - Option 4 : 6 litres

Given:

The initial quantity of mixture containing milk and water is 156 liters.

	Milk : Water
Initial	7 : 6
New	14 : 13

 

Calculation:

Let the water to be added be x litres.

Then, initial quantity of milk = {7/(7 + 6)} × 156 liters

⇒ (7/13) × 156 litres

⇒ 84 litres

And, initial quantity of water = {6/(7 + 6)} × 156 liters

⇒ (6/13) × 156 litres

⇒ 72 litres

Now, 84/(72 + x) = 14/13

⇒ 84 × 13 = 14 × (72 + x)

⇒ 6 × 13 = 72 + x

⇒ x = 78 – 72

⇒ x = 6

∴ The quantity of water added is 6 litres.