posted by jenny .
A paint-mixing machine has 2 inlet pipes. One takes 1 hour less than the other to fill the tank. Together they fill the tank in 3 hours. How long would it take each of them alone to fill the tank?
time=1/(1/timefast + 1/(timefast+1)
3(1/timefast + 1/(timefast+1))=1
solve for timefast. For the other unit, add one hour.
multiply tf(tf+1) to each side to get started.