SOLUTION: WHAT IS THE RATIONAL EQUATION IF DAN AND LAURA TAKE 9 HOURS TOGETHER TO MAKE WEDDING INVITATIONS, BUT IT TAKES LAURA 15 HOURS ALONE. HOW LONG WILL IT TAKE DAN BY HIMSELF.

Algebra ->  Algebra  -> Polynomials-and-rational-expressions -> SOLUTION: WHAT IS THE RATIONAL EQUATION IF DAN AND LAURA TAKE 9 HOURS TOGETHER TO MAKE WEDDING INVITATIONS, BUT IT TAKES LAURA 15 HOURS ALONE. HOW LONG WILL IT TAKE DAN BY HIMSELF.      Log On

Ad: Algebra Solved!™: algebra software solves algebra homework problems with step-by-step help!
Ad: Algebrator™ solves your algebra problems and provides step-by-step explanations!

   

Question 28889: WHAT IS THE RATIONAL EQUATION IF DAN AND LAURA TAKE 9 HOURS TOGETHER TO MAKE WEDDING INVITATIONS, BUT IT TAKES LAURA 15 HOURS ALONE. HOW LONG WILL IT TAKE DAN BY HIMSELF.
Answer by stanbon(48569) About Me  (Show Source):
You can put this solution on YOUR website!
Let amount of time it takes Dan alone be "x".
His rate is 1/x per hour.
Laura takes 15 hours; her rate is 1/15 per hour.
Together they take 9 hours; their combined rate is 1/9 per hour.
EQUATION:
Dan rate + Laura rate = together rate
1/x + 1/15 = 1/9
Multiply thru by 45x to get:
45+3x = 5x
2x=45
x=22.5 hours.
Dan takes 22.5 hours to do the job alone
Cheers,
Stan H.