SOLUTION: if jeanne can type 20 pages in 40 minutes and jim can type 20 pages in 30 minutes, how long will it take them to type 20 pages working together?

Click here to see ALL problems on Rate-of-work-word-problems

Question 165572: if jeanne can type 20 pages in 40 minutes and jim can type 20 pages in 30 minutes, how long will it take them to type 20 pages working together?
Found 2 solutions by Mathtut, ptaylor:
Answer by Mathtut(3670) (Show Source):
You can put this solution on YOUR website!
jean types at a rate of 1/2 page per minute 20/40
Jim types at a rate of 2/3 page per minute 20/30
together: would be 1/2t+2/3t=20 where t is time.
find a common denominator and you get 7/6t=20 multiply both sides by 6 and you get 7t=120 so t=appx 17.1 minutes

Answer by ptaylor(2198) (Show Source):
You can put this solution on YOUR website!
Let x=time it takes to type 20 pages when both are working together
So, 20/x=rate at which they work when working together
Jeanne types at the rate of 20/40=1/2 page per min
Jim types at the rate of 20/30=2/3 pages per min
Together they work at the rate of 1/2 + 2/3 =7/6 pages per min
So, our equation to solve is:
(7/6)*x=20 multiply each side by6
7x=120
x=17.143 min
Another way:
7/6=20/x multiply each side by 6x
7x=120-----------same as before
CK
(1/2)*17.143= 8.571 pages
(2/3)*17.143=11.429 pages
8.571 + 11.429=20
20=20

Hope this helps---ptaylor