In 80 litres mixture of milk and water, the ratio of amount of milk to that of amount of water is 7 : 3. In order to make this ratio 2 : 1, how many litres of water should be added?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 4 litres
Adding water does not change the amount of milk, so the milk fixes how much water the new ratio needs.
Milk \(\displaystyle =\frac{7}{10}\times80=56\) litres; water \(=80-56=24\) litres
For milk : water \(=2:1\), water must be half the milk: \(56\div2=28\) litres
Water to be added \(=28-24=4\) litres