Question

A and B working together can do a piece of work in 12 days . B alone can do the same work in 20 days .How long will A take to do the same work ?i) find A and B together one day work ii) B's one day work iii) A's one day's work iv) Time taken by A to do the same work *​

Answer 1

Both A and B can complete 1/12th work in one day

So A+B=1/12 in one day

B alone can complete 1/20th work

B=1/20 in one day

Now A alone how much work can complete,so

(1/20)+A=1/12

A =(1/12)-(1/20)

L.C.M of 12 and 20 is 60

So A =( (5–3)/60)

A=2/60=1/30

So alone can complete 1/30th work in one day

A alone can complete the work in 30 days