SOLUTION: Working together, pump c and d can drain 2 pools in 21 hours. How long would it take each pump working individually to drain 2 pools if it takes pump d 3 hours longer per one pool?

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Working together, pump c and d can drain 2 pools in 21 hours. How long would it take each pump working individually to drain 2 pools if it takes pump d 3 hours longer per one pool?      Log On


   

Question 1176002: Working together, pump c and d can drain 2 pools in 21 hours. How long would it take each pump working individually to drain 2 pools if it takes pump d 3 hours longer per one pool?
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
The question is about TWO jobs, and then "Drain ONE pool" is ONE job. 
PUMP         RATE for 1 JOB
c               1/c
d               1/(c+3)
combined        1/21


RATE multiply by TIME is HOW MANY JOBS.

%281%2Fc%29%2A21%2B%281%2F%28c%2B3%29%29%2A21=2
Simplify and solve.