SOLUTION: Two people are painting a 10' by 8' wall. The first person paints the wall in 3 hours. The second person paints it in 2 hours. If they work together, how long will it take them to

Algebra ->  Equations -> SOLUTION: Two people are painting a 10' by 8' wall. The first person paints the wall in 3 hours. The second person paints it in 2 hours. If they work together, how long will it take them to       Log On


   

Question 877021: Two people are painting a 10' by 8' wall. The first person paints the wall in 3 hours. The second person paints it in 2 hours. If they work together, how long will it take them to paint the wall?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Add their rates of painting to get
their rate painting together
1st person:
( 1 wall ) / ( 3 hrs )
2nd person:
( 1 wall ) / ( 2 hrs )
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Working together:
( 1 wall ) / ( t hrs )
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+1%2F3+%2B+1%2F2+=+1%2Ft+
Multiply both sides by +6t+
+2t+%2B+3t+=+6+
+5t+=+6+
+t+=+6%2F5+
+t+=+1+%2B+1%2F5+
Note that +1%2F5+ hr = +%281%2F5%29%2A60+=+12+ min
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Working together, it will take
them 1 hr and 12 min