Question

A 40-litre mixture contains milk and water in the ratio 3 : 1. How many litres of water must be added to make the ratio 1 : 1?

• A. 10 litres
• B. 15 litres
• C. 20 litres
• D. 25 litres

Hint:

Only water is added, so milk stays at 30 L.

Answer 1

The Correct Option is C

Step 1: Find the current amounts.
Total 40 L in ratio 3 : 1: milk \(= \dfrac{3}{4}\times 40 = 30\) L, water \(= 10\) L.
Step 2: Milk stays fixed; find required water.
For a 1 : 1 ratio, water must equal milk \(= 30\) L.
Step 3: Water to add.
\[30 - 10 = \boxed{20 \text{ litres}}\]