Question

7. QUESTION
Category: Quantitative
A can do a piece of work in 40 days and B in 60 days. Both of them start working together and 4 days before the scheduled completion. A drops
out By how many days is the work extended beyond the normal schedule?
8 days
8.33 days
10 days
6 days​

Answer 1

Answer:

Let the (total) work consists of 2400 small jobs. Since A (alone) takes 60 days to do it, A is capable of doing 40 small jobs (2400/60 = 40) per day. Now, B (alone) takes 40 days to do it, B is capable of doing 60 small jobs (2400/40 = 60) on a daily basis.

Thus, you will see, A and B together can do 60 + 40 = 100 small jobs in a day.

So, together they would take 24 days (2400/100 = 24) to do the (total) work. But together they just worked for only 12 days i. e. they finished only half the work together, when A went away.

Now, since B takes 40 days to do the work, he would take 20 days (since only half the work is left) further, to finish the remaining work.

So, 20 is the required answer.

Step-by-step explanation: