Question

A and B can do a piece of work in 15 days and 20 days respectively.[ 3+3+4 ] Find the work done by A in 3 days ​

Answer 1

Answer:

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Answer 2

Given A can do the work in 20 days and B can do it 15 days.

Then work done by A in one day =1/20

And, work by B in one day =1/15

Then, the work done by A & B in one day =1/20+1/15=7/60

A & B done 6 days together then work done in A & B in 6 days =7/60×6=7/10

Then friction of work left =1−7/10 = 3/10

Then B can  do  3/10  work =3/10×15/1=9/2=4 1/2 days