If A is thrice as fast as B and B takes #60# days more to finish a work, than how much time they will take to finish the work together?

1 Answer
Aug 2, 2017

Together they can do the job in #15# days.

Explanation:

Let us suppose #B# finish the job in #x# days.

So, in one day #B# does #1/x# of the job.

As #A# is thrice as good a workman as #B#,

in one day he does #3xx1/x=3/x# of the job

and he will finish the job in #x/3# days

As such #x-x/3=(2x)/3=60#

hence #B# does #1/60# of job in one day and #A# does #3/60# of job in one day

and they together do #1/60+3/60=4/60=1/15# of job in one day.

Hence, together they can do the job in #15# days.