<pre>
If Sally can paint a house in 4 hours, and John can paint the same house in 6
hour, how long will it take for both of them to paint the house together? 
I did not get the answer to this problem, so if you could please give me some
solutions.
<b>
Let x = the number of hours it will take them painting together

Then their combined rate = (1 house)/(x hours) or 1/x house/hr

>>...Sally can paint a house in 4 hours...<<

Translation:  Sally's rate is (1 house)/(4 hours) or 1/4 house/hr

>>...John can paint the same house in 6 hour...<<

Translation: John's rate is (1 house)/(6 hours) or 1/6 house/ hr

To form the equation:

Sally's rate + John's rate = their combined rate

1/4 + 1/6 = 1/x

Can you solve that?  (Hint: get LCD = 12x and multiply thru)

Answer: 2.4 hours or 2 hours 24 minutes

Edwin
AnlytcPhil@aol.com</pre>