Question

Worker A take 8 hours to do a job. Worker B take 10 hours to do a job. How long should it take both A and B working together to do a same job??

Answer 1

(A)'s 1 hour work= 1/8
(B)'s 1 hour work= 1/10
(A+B) 's work together = 1/8+1/10
= 1/40
( A+B) = 40 hours