Aman, Bittu, and Chintu can each complete a task in 20, 30, and 60 days, respectively. How many days will it take for Aman to finish the work if he is helped by Bittu and Chintu on every third day?

Aman's work rate: 1/20 (since he finishes the work in 20 days). Bittu's work rate: 1/30 (since he finishes the work in 30 days). Chintu's work rate: 1/60 (since he finishes the work in 60 days).

Work done in a 3-day cycle: Days 1 and 2: Only Aman works, completing 1/10 of the work in 2 days. Day 3: Aman, Bittu, and Chintu work together, completing 1/10 of the work.

So, in each 3-day cycle, they complete 2/10 =1/5 of the work.

Total time = To complete the entire work, it will take 5 cycles (since = 1/(1/5) = 5

Each cycle takes 3 days, so the total time is 5×3 = 15 days.

It will take 15 days for the work to be completed.