Multiple choice

A mixture contains two liquid A and B in the ratio 4: 1. If 10 liters of the mixture is replaced with 10 litres of liquid B, the ratio becomes 2: 3. How many litres of liquid A was in the mixture?

  1. 10 litres

  2. 12 litres

  3. 16 litres

  4. 18 litres

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

Let initial A = 4x, B = x. Total = 5x. After removing 10 litres (8A, 2B) and adding 10B: A = 4x-8, B = x-2+10 = x+8. New ratio (4x-8):(x+8) = 2:3. Cross-multiply: 3(4x-8) = 2(x+8). Solving: 12x-24 = 2x+16, so 10x = 40, x = 4. Initial A = 4x = 16 litres.