Working together in Sales

Michael Scott, by himself, can close 8 sales in 4 hours. If he works with Dwight, they can close 8 sales in 2 hours. How many hours does it take Dwight to close 8 sales by himself?

For Michael, 8 sales in 4 hours means 2 sales per 1 hour or 2/1

Michael's sales / hour + Dwight's sales / hour = together's sales per hour

Dwight's sales / hour is x/1

Together, 8 sales in 2 hours means 4 sales per 1 hour or 4/1

2/1 + x/1 = 4/1

2 + x = 4

2 - 2 + x = 4 - 2

x = 2

So Dwight can do 2 sales per hour. It is basically the same as Michael. In this case, he can also do 8 sales in 4 hours.