Raja and Rocky together can complete painting work in 5 days. Together, they both start painting, but after 2 days, Rocky falls sick and leaves the work. If Raja completes the remaining painting in 4 days, find the number of days in which Rocky alone can do the work.
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 20 days.
Given:
Raja and Rocky, together, can complete painting work in 5 days
Calculations:
Let the efficiency of Raja and Rocky be X and Y
According to the question;
⇒ 2(X + Y) + 4X = 5(X + Y)
⇒ 2X + 2Y + 4X = 5X + 5Y
⇒ X = 3Y
⇒ X/Y = 3/1
Total work = 5 × (3 + 1) = 20
Hence, Rocky alone can do the work in = 20/1 = 20 days