25 kg of alloy X is mixed with 125 kg of alloy Y

25 kg of alloy X is mixed with 125 kg of alloy Y. If the amount of lead and tin in the alloy X is in the ratio 1:2 and the amount of lead and tin in the alloy Y is in the ratio 2:3, then what is the ratio of lead to tin in the mixture?

  1. 1:2
  2. 2:3
  3. 3:5
  4. 7:11

Answer

Lead in the mixture = (1/3 × 25) + (2/5 × 125) = 175/3 kg

Tin in the mixture = (2/3 × 25) + (3/5 × 125) = 275/3 kg

Ratio of lead to tin in the mixture = 175 : 275 = 7:11

The correct option is D.