Question

a started a work and left working after 14 days now B finish the remaining work in 20 days.had A left the work after working for 7 Daysthen B would have finished the remaining work in next 25 days then find how many days A and B together can complete the work ?​

Answer 1

Answer:

Let A can finish work in x days and B in y days.

Then in 1 day A can do 1/x work and B can do 1/y work.

In 14 days A will finish 14/x work. Remaining amount of work=1-(14/x) which B finishes in 20 days.

In 20 days B can do 20×(1/y) work. So

1-(14/x)=20/y

20/y+14/x=1 equation 1

Similarly you can write

1-(7/x)=25/y

25/y+7/x=1 equation 2

Multiply equation 2 by 2 and subtract from equation 1, you will get

(20/y)-(50/y)=-1

y=30

put this value of y in any of the above equations you will get

x=42

Together A and B can finish (1/30)+(1/42) work in 1 day

=

2/35 work in 1 day

So 1 work (full work) they will finish in 35/2 days

Normally equation 1 and 2 are written as

20u+14v=1

and then solved for u and v from which x and y values are determined.