Question

A can do a piece of work in 20 days and B can do it in 12 days. B
worked for 9 days and quit. In how many days can A alone finish
the remaining work?​

Answer 1

B's 9 day's work = ( 1/12×9) =3/4

Remaining work = 1−3/4=1/4

1/20 work is finished by A in 1 day.

1/4 work is finished by A in (20× 1/4) =5 days