Q1.A and B can do a work in 8 days ,B and C can do the same work in 12 days. A , B, C together can finish it in 6days. A and C together will do it in ?
Answers
Explanation:
Given
A and B can do work in 8 days.
B and C can do work in 12 days
A,B,C can do work together in 6 days.
To find
A and C will complete work in how many day
Since A and B can do work in 8 days
Then, Equation becomes : A+B= 8
➙(A+B)'s one day work = 1/8
B and C can do work in 12 days
Then Equation becomes : B+C= 12
➙(B+C)'s one day work = 1/12
A,B,C together can finish the work in 6 days
Then , Equation becomes : A+B+C= 6
➙(A+B+C)'s one day work = 1/6
Then (A+B) and (B+C) can do work => 1/8+1/12 = 5/24
=> A+B+B+C = 5/24
=> A+2B+C = 5/24------(1)
=>A+B+C= 1/6---------(2)
Solving equation 1 and 2
➙A+2B+C= 5/24
➙A+B+C= 1/6
Substract Equation 2 from 1
➙ A+2B+C-(A+B+C)= 5/24-1/6
➙A+2B+C-A-B-C= 5-4/24
➙B= 1/24----(3)
Put B's value into this equation
➙A+B+C= 1/6
➙A+1/24+C= 1/6
➙A+C= 1/6-1/24
➙A+C= 4-1/24
➙A+C= 3/24=1/8
Therefore,A and C together can finish work in 8 days.