A and B can finish a work in 6 days and 4 days, respectively. A alone worked on it for 2 days. Thereafter, B joined him. How much total time was taken by them to finish the work?

Explanation

Given A and B can finish a work in 6 days and 4 days Formula used Work = time × efficiency Calculation A, alone worked for 2 days. Work done by A in 2 days = 2/6 = 1/3 Work done by A and B in 1 day = 1/6 + 1/4 = 5/12 Let the number of days worked by both be N. ⇒ 5/12 × N = 1 - 1/3 N = 8/5 Total time = 2 + 8/5 = 18/5 or 3(3/5) days The answer is 3(3/5) days.