SOLUTION: Mary can paint a house in 4 hrs.John can paint the same house in 6 hrs. How long will it take to paint house together. First I converted hours to minutes, added them together, the

Algebra ->  Sequences-and-series -> SOLUTION: Mary can paint a house in 4 hrs.John can paint the same house in 6 hrs. How long will it take to paint house together. First I converted hours to minutes, added them together, the      Log On


   



Question 274937: Mary can paint a house in 4 hrs.John can paint the same house in 6 hrs. How long will it take to paint house together. First I converted hours to minutes, added them together, then divided by two. please help me set up this problem correctly.
Found 2 solutions by Alan3354, ankor@dixie-net.com:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Mary can paint a house in 4 hrs.John can paint the same house in 6 hrs. How long will it take to paint house together. First I converted hours to minutes, added them together, then divided by two. please help me set up this problem correctly.
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Instead of converting to minutes, you could have added 4 hours and 6 hours = 10 hours. It still wouldn't be right.
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Mary paints 1/4 of the hours per hour.
John paints 1/6 per hour.
Add those up --> 1/4 + 1/6 = 5/12 per hour
--> 12/5 hours to do the job = 2.4 hours
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Use the shortcut, product/sum
4*6/(4+6) = 24/10 = 2.4 hours

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Mary can paint a house in 4 hrs.John can paint the same house in 6 hrs.
How long will it take to paint house together
:
You have to use the "shared work equation"
where
t = time (in hrs) required when working together
and
completed job = 1 (a painted house)
:
Each will do a fraction of the job, the two fractions add up to 1
t%2F4 + t%2F6 = 1
:
That's the setup. Email me if you have difficulty with it: ankor@att.net