Question

A and b together complete a peice of work in T days .if A alone complete the work in T+3 days and b alone complete the work in t+12 days what is t

Answer 1

(1/t+3) + (1/t+12) = 1/t
t(2t+15) = (t+3)*(t+12)
2t^2 + 15t = t^2 + 15t + 36
t^2 = 36 ; t=6