SOLUTION: Two taps A and B can fill a tank in 3 hours and 20 minutes. When tap A alone is open, it takes 2 hours more to fill the tank, than when B alone is open. Assuming uniform flow, bow

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Two taps A and B can fill a tank in 3 hours and 20 minutes. When tap A alone is open, it takes 2 hours more to fill the tank, than when B alone is open. Assuming uniform flow, bow       Log On


   

Question 744182: Two taps A and B can fill a tank in 3 hours and 20 minutes. When tap A alone is open, it takes 2 hours more to fill the tank, than when B alone is open. Assuming uniform flow, bow long does it take for B alone to fill the tank?
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
This is a job rate or task completion problem.

tap A plus tap B, rate is 1%2F%283%261%2F3%29 job per hour.
tap B, rate? Let's use h for the hours to do the job. It's not the rate, but for now it will help.
tap A, rate is 1%2F%28h%2B2%29 job per hour.

So then how do we express the rate for tap B? This rate is 1%2Fh job per hour.

Notice that I have been using rate as JOBS per HOUR, and not HOURS per JOB. Addition of rates for agents which work simultaneously is easier to manage this way.

rate for tap A + rate for tap B = combined rate of tab A AND tap B;
highlight%281%2F%28h%2B2%29%2B1%2Fh=1%2F%283%261%2F3%29%29.
Solve for h.
THAT is the time for tap B to fill the tank if tap B works alone.