SOLUTION: Rosita can wax her car in 1hr(s). When she works together with Debbie, they can wax the car in 15 min(s). How long would it take Debbie, working by herself, to wax the car? Hint: c

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Rosita can wax her car in 1hr(s). When she works together with Debbie, they can wax the car in 15 min(s). How long would it take Debbie, working by herself, to wax the car? Hint: c      Log On


   



Question 520542: Rosita can wax her car in 1hr(s). When she works together with Debbie, they can wax the car in 15 min(s). How long would it take Debbie, working by herself, to wax the car? Hint: convert hours to minutes.
Found 2 solutions by scott8148, edjones:
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
not sure if that's a good hint

in the 15 min it takes working together, Rosita does 1/4 (15 min / 1 hr)
___ so Debbie does 3/4 in 15 min ___ she does 1/4 in 5 min (15 / 3)
___ so she can do 4/4 (the whole car) in 20 min (5 * 4)

Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
Rosita can do 1/60 job in 1 min.
d=minutes it takes Debbie to do the job. Debbie can do 1/d the job in 1 min.
Together they can do 1/15 the job in 1 min.
1/60 + 1/d = 1/15
d+60=4d Multiply by 60d.
3d=60
d=20 min
.
Ed