SOLUTION: A man can harvest his farm in 18 hours. His son can harvest the same farm in 12 hours. How long will it take them working together? I know the answer is 7.2, I need to know how to

Algebra ->  Human-and-algebraic-language -> SOLUTION: A man can harvest his farm in 18 hours. His son can harvest the same farm in 12 hours. How long will it take them working together? I know the answer is 7.2, I need to know how to      Log On


   

Question 761782: A man can harvest his farm in 18 hours. His son can harvest the same farm in 12 hours.
How long will it take them working together? I know the answer is 7.2, I need to know how to write equation to come up with answer.
Answer by Cromlix(4381) About Me  (Show Source):
You can put this solution on YOUR website!
1/18 +1/12 = 1/x rate
Denominator = 36x
2x + 3x = 36
5x = 36
x = 7.2 hours
Hope this helps.
:-)