Question

A can do a piece of work in 14 days which B can do it in 21 days athey begin together but 3 days before completion of the work, A leaves off. Find the total number of days taken to complete the work​

Answer 1

(A+B)

′

s1 day work

=

14

1

+

21

1

=

42

3+2

=

42

5

At the end, B works for 3 days so work done by B in 3 days=3×

21

1

=

7

1

.

Remaining work 1−

7

1

=

7

6

which is to be done by A and B.

42

5

of work (A+B) can do in 1 days

∴

7

6

of work (A+B) can do in

5/42

1

×

7

6

=7

5

1

days

∴ Time to complete the work

=3+7

5

1

=10

5

1

days.