SOLUTION: John can complete the job in 6 hours, and Sue can complete the job in 4 hours. How long does it take them to complete the job when they work together?

Algebra ->  Rate-of-work-word-problems -> SOLUTION: John can complete the job in 6 hours, and Sue can complete the job in 4 hours. How long does it take them to complete the job when they work together?       Log On


   

Question 366898: John can complete the job in 6 hours, and Sue can complete the job in 4 hours. How long does it take them to complete the job when they work together?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


Hi, 

Let x represent the time it takes them together

Using perhour as an equalizer

1/6hrs + 1/4hrs = 1/x

mutiplying each term on both sides o fequation by 12x, so as all denonminators = 0

2x + 3x = 12

5x = 12

x = 12/5 Or  2 2/5 hrs Or 2hr and 24 min