Question

A, B and C can do a work in 12
, 15 and 20 days respectively. They started working together but after 4 days A left
In how many days will B and C complete the work? in mixed fraction
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Answer 1

Answer:

Step-by-step explanation:

A's one day's work=1/12

B's one day's work=1/15

C's one day's work=1/20

A,B and C's one day's work

=1/12+1/15+1/20=(5+4+3)/60=12/60=1/5

In 4 days the work done=4/5

left work=1/5=4/20

B  and C 's  one day work

=1/15+1/20

=(4+3)/20=7/20

So time taken

=(4/20) / (7/20)=1/5 *20/7

=4/7 days