SOLUTION: A tap X and Y can fill up an empty tank in 15 and 12 hours respectively. another tap z can empty the full tank in 8 hours. if all the tap turned together at the same time, in ho

Algebra ->  Rate-of-work-word-problems -> SOLUTION: A tap X and Y can fill up an empty tank in 15 and 12 hours respectively. another tap z can empty the full tank in 8 hours. if all the tap turned together at the same time, in ho      Log On


   

Question 839595: A tap X and Y can fill up an empty tank in 15 and 12 hours respectively. another tap z can empty the full tank in 8 hours. if all the tap turned together at the same time, in how many hours will the tank be full?
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
Find the rate of filling, as tankfulls per hour.
1%2F15%2B1%2F12-1%2F8
LCD is 2*2*2*3*5
8%2F120%2B10%2F120-15%2F120
3%2F120
highlight_green%281%2F40%29, tanks per hour.

Uniform rate equation for filling the tank is %281%2F40%29%2At=T
t = time in hours
T = how many or how much tank to fill
You are interested in filling 1 tank, so T=1.
Specific equation to solve is highlight%28%281%2F40%29t=1%29; solve for t.