# 25 men are employed to do a work in, which they could finish in 20 days but they drop off by 5 men at the end of every 10 days. In what time will the work be completed?

##### 2 Answers

The work finishes on the 24th day.

#### Explanation:

We start with 25 men. They can do a job in 20 days. This means that the 25 men finish

At the end of 10 days, the 25 men will have finished:

And now we drop off 5 men, leaving 20 left. We have

Now the job is

And they do. In fact, they can do the remaining work 3 times over. This means they'll finish on the 4th day:

The time taken will be

#### Explanation:

We are working with inverse proportion where, as the number of people decreases, the time taken to finish a task will increase.

Find the constant first.

The total task requires

In the first

For the next

The amount of work completed is:

There are then

The work can be completed in:

The total time taken is therefore

The work will be completed on the