Question

a alone can do a work in 12 days and b can do it in 15 days what part of work will they do in 3days

Answer 1

a will do 1/4work in 3 day
b will do 1/5work in 3 day

Answer 2

hye
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a can do a work in 12 days = 1/12

b can do a work in 15 days  = 1/15 

we have to find what part of work will they do in 3days 

work they do in 1 day = 1/12+ 1/15 = 9/60 = 3/20

one day they do 3/20

then 3days = 3/20× 9

                     =9/20
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hope it helps
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