# 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 $\frac{1}{10} t h$ of the wall.

Similarly, it takes Jim 6 hours to construct the wall. Therefore, in 1 hour, Jim constructs $\frac{1}{6} t h$ of the wall.

Hence, if they work together, the amount of wall constructed in 1 hour will be $\frac{1}{10} + \frac{1}{6} = \frac{3 + 5}{30} = \frac{8}{30}$.

We know, now, that in 1 hour, $\frac{8}{30} t h$ of the wall would be constructed. Therefore, the time required to construct the full wall will be $\frac{30}{8} = 3.75$ hours.