Question

two men can do a piece of work in 6 hour and 4 hours respectively after the first has worked for 2 hours he is joined by otherby when should the work be completed

Answer 1

speed of first man: 1/6 piece of work per hr speed of second man:1/4 piece of work per hr Let t be the time taken by the two men after the first man is joined by the 2nd man 2 x 1/6 + t x 1/4 + t x 1/6= 1 1/3 + t (1/4 + 1/6) = 1 t = 1.6 hrs Total time taken = 2 + 1.6 = 3.6 hrs