Time and Work | Time and Work Exercise 11.1

Question

A and B can finish a work in 20 days. A alone can do 1/5th of the work in 12days. In how many days can B alone do it?

Accepted Answer

The given details are,

A and B can finish a work in = 20 days

(A+ B)’s 1 day work = 1/20

A can finish 1/5th of work in = 12 days

A’s 1 day work = 1/(5×12) = 1/60

We know that,

B’s 1 day work = (A+B)’s 1 day work – A’s 1 day work

= 1/20 – 1/60

= (3-1)/60

= 2/60

= 1/30

∴ B alone can finish the work in = 1/(1/30) = 30days.

Question 11