A and B can polish the floors of a building in 10 days. A alone can do `(1/4)^(th)` of it in12 days. In how many days can B alone polish the floor?

Explanation

A and B can polish a building in = `'10'` days
Work done by A and B in one day = `'1/10'`
A alone can do `1/4th` of work in = `'12'` days
A’s `'1'` day work = `'1/(4×12)'`
= `'1/48'`
We know that,
B’s `'1'` day work = `(A+B)’s 1` day work –` A’s '1'` day work.
=` '1/10 – 1/48'`
=` '(48-10)/480' `
(by taking LCM for `'10'` and `'48'` which is `'480'`)
=` '38/480'`
= `'19/240'`
B alone can polish the floor in = `'1/(19/240) `
= `'240/19' `
= `'12 12/19' `days.