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
Veerupaksh
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 #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.

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