Multiple choice

The ratio of efficiency of A,B,C is 4:5:3. Working together, they can complete that work in 25 days. A and C together will complete 35% of that work in how many days?

  1. 12

  2. 10

  3. 18

  4. 15

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

Let efficiencies be 4k, 5k, 3k for A,B,C. Combined efficiency = 12k units/day. In 25 days, total work = 25×12k = 300k units. A and C together have efficiency 7k units/day. To complete 35% of work = 0.35×300k = 105k units, they need 105k/(7k) = 15 days.