Question

A nad B together can do a piece of work in 12 days, while B alone can finish it in 30 days. In how many days can A alone finish the work??​

Answer 1

Answer:

A alone finish the work in 20 days

Step-by-step explanation:

Given : A and B can do a piece of work in 12 days

           B alone can finish it in 30 days

           A alone can finish in how many days = let be A days

Solution : B alone can finish it in 30 days

                In a day B alone can finish 1/30 of work

                In one day A can finish 1/A work

∴ Together A & B can finish 1/12 of work in 1 day

i.e. 1/A + 1/30 = 1/12

     1/A = 1/12 - 1/30

           = (5-2)/60            LCM 0f 12 & 30 is 60

           = 3/60

    1/A  = 1/20

∴      A = 20 hrs