Question

a and b can do a work in 8days b and c can do a work in 12 days a b c together can finish the work in 6 days then find a and c together will do it in how many days

Answer 1

Let A and C complete the work in x days
 (A+B)’s one day’s work= 1/8
(B+C)’s one day’s work= 1/12
(C+A)’s one day’s work= 1/x
Then (A+B+B+C+C+A)’s one day’s work = 1/8+1/12+1/x
2(A+B+C)’s one day’s work = 3x+2x+24x/24x
(A+B+C)’s 1 day’s work = 5x+24/24x*2
According to the question (A+B+C)’s 1 day’s work =1/6
= 1/6= 5x+24/24x*2
= 30x + 144= 48x
therefore, x= 144/8 
                     = 8 days