Question

A does 80% of work in 20 days. He then calls in B and they together finish the remaining work in 3 days. How long B alone would take to do the whole work?

विकल्प

• 23 days

• 37 days

• `37 1/2`days

• 40 days

Answer 1

`37 1/2`days

Explanation:

Whole work is done by A in `(20xx5/4)` = 25 days

Remaining work `1/5`is done by A and B in 3 days. 
Whole work will be done by A and B in (3 x 5) = 15 days

A's 1 day's work = `1/25`

(A + B)'s 1 day's work = `1/15`

∴ B's 1 day's work = `(1/15-1/25)=4/150=2/75`

So, B alone would do the work in = `75/2=37 1/2`days