Barney can mow the lawn in 5 hours, and Fred can mow the lawn in 4 hours. How long will it take them to mow the lawn together?
To find out how long it will take them to mow the lawn together, we can use the formula:
1/Time Taken = 1/Time A + 1/Time B
Let's plug in the given values:
1/Time Taken = 1/5 + 1/4
To simplify this equation, we need to find a common denominator. In this case, it is 20.
1/Time Taken = 4/20 + 5/20
1/Time Taken = 9/20
We can flip both sides of the equation to get:
Time Taken = 20/9
So, it will take them approximately 2.22 hours to mow the lawn together.