Multiple choice

The milk and water in a mixture are in the ratio 7 : 5. When 15 litres of water are added to it, the ratio of milk and water in the new mixture becomes 7 : 8. The total quantity of water in the new mixture is :

  1. 35 litres

  2. 40 litres

  3. 60 litres

  4. 96 litres

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let initial quantities be 7x milk and 5x water. After adding 15 litres water, new water is 5x + 15. New ratio 7:8 gives 7x/(5x+15) = 7/8, so 8(7x) = 7(5x+15), meaning 56x = 35x + 105, thus 21x = 105 and x = 5. New water = 5(5) + 15 = 25 + 15 = 40 litres.