Question

A can do a piece of work in 10 days and B in 20days they begin together but A leaves 2 days before the complete of the work in how many days will the whole work be complete

Answer 1

let the total work be 1

therefore,

work done by A in 10 days= 1

work done by A in 1 day= 1/10

also,

work done by B in 20 days= 1

work done by B in 1 day= 1/20

therefore work done by both= 1/10+1/20

=3/20

since, A leaves 2 days before the work is completed

which means that B will do the rest 2 days. so,

B does 1/20 work in 1 day

therefore,

work done in 2 days= 1/10

therefore remaining work= 1-1/10

=9/10

the remaining work will be done by both A and B

since, work done by both (A and B) in 1 day= 3/20

therefore time taken to do 1 work= 20/3

so, time taken to do 9/10 work= 9/10× 20/3

= 6 DAYS

therefore, total time taken = 6+2

= 8 DAYS