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?

1 Answer
May 1, 2017

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 110th of the wall.

Similarly, it takes Jim 6 hours to construct the wall. Therefore, in 1 hour, Jim constructs 16th of the wall.

Hence, if they work together, the amount of wall constructed in 1 hour will be 110+16=3+530=830.

We know, now, that in 1 hour, 830th of the wall would be constructed. Therefore, the time required to construct the full wall will be 308=3.75 hours.