Posted by Laowe on .
It takes Todd 3 hours longer than Tom to paint a 4x5 feet bedroom. Working together, both can complete the job in two hours.How long does it take each one to complete the painting job working alone?

College Algebra 
Mgraph,
Let it takes Todd X hours; Tom Y hours.
X=Y+3
For one hour, Todd paints 1/X part of the bedroom, Tom  1/Y; together  1/X+1/Y
1/(1/X+1/Y)=2
2(X+Y)=XY
2(2Y+3)=(Y+3)Y
4Y+6=Y^2+3Y
Y^2Y6=0 => Y=3, X=6