Question

12. A can do a piece of work in 20 days which B alone can do in 12 days.
13. A can do a piece of work in 25 days, which B alone can do in 20 days. A started the work and
9 days. A can finish the remaining work in
(b) 5 days
te) 7 days
(a) 3 days
(d) 11 days
was
joined by B after 10 days. The work lasted for
1
2
a) 14 days​

Answer 1

Lets give the piece of a work a nice round number, 100

So the ‘piece of work’ takes 100 units to complete.

If A can do it in 20 days, they are doing 100/20 units of work per day

100/20 = 5.

B can do the 100 units in 12 days

100/12 = 8.33..

If B does 9 days worth of work, that will be 9 * 8.33… = 75 units.

We need to subtract 75 from the original 100 units of work to see how much work is left to do.

100 -75 = 25 units of work.

Given A does 5 units of work a day, we divide 25 by 5 to tell us how many days it will take to finish the remaining work

25/ 5 = 5

Thus it will take 5 days for A to finish the remaining work.

DEADSOUL ✝️☠️