SOLUTION: bob fills a pool in 30 min, joe does it in 45 min frank takes 90 minutes - how may minutes will it take them all to fill the pool?

Algebra ->  Algebra  -> Customizable Word Problem Solvers  -> Numbers -> SOLUTION: bob fills a pool in 30 min, joe does it in 45 min frank takes 90 minutes - how may minutes will it take them all to fill the pool?      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com
Ad: Algebrator™ solves your algebra problems and provides step-by-step explanations!
Ad: Algebra Solved!™: algebra software solves algebra homework problems with step-by-step help!

   

Question 206789: bob fills a pool in 30 min, joe does it in 45 min frank takes 90 minutes - how may minutes will it take them all to fill the pool?
Answer by scott8148(5891) About Me  (Show Source):
You can put this solution on YOUR website!
they each fill a fraction of the pool based on their own times
___ the fractions sum to 1 (the whole pool)

let x="combined time"

x/30 + x/45 + x/90 = 1

multiplying by 90 (LCD) ___ 3x + 2x + x = 90 ___ 6x = 90 ___ x = 15