Question

It takes Sam 10 hours to construct a wall of a certain size. It takes Jim 6 hours to construct the same wall. How long would it take if they worked together?

Answer 1

`3.75` hours.

Explanation:

We can tackle such type of problem in the following way:-

It takes Sam 10 hours to construct a wall. It means that in 1 hour, Sam constructs `1/10th` of the wall.

Similarly, it takes Jim 6 hours to construct the wall. Therefore, in 1 hour, Jim constructs `1/6th` of the wall.

Hence, if they work together, the amount of wall constructed in 1 hour will be `1/10+1/6 = (3+5)/30 = 8/30`.

We know, now, that in 1 hour, `8/30th` of the wall would be constructed. Therefore, the time required to construct the full wall will be `30/8 = 3.75` hours.