A can do thrice 85 much work as ‘B’ does and five times as much work as ‘C’ does. If A can complete a task in 23 days, then working together, how long will all three of them take to complete the task?

Explanation:

A can do thrice as much work as ‘B’ does and five times as much work as ‘C’ does. If A can complete a task in B/3 days (or) C/5 days to complete the job.

If A takes 23 days, B takes 23×3=69 days and C takes 23×5 = 115 days to complete the work.

Therefore, 1\A+1\B+1\C=1\23+1\69+1\115=15+5+3\23×3×5=1\15

Or A, B and C together will complete the job in 15 days.