algebra
posted by floyd .
At the station, you fill the tank. You use an overhead fill that puts out 162 gallons per minute. How long will it take to fill the tank?

I'd guess that depends on the size of the tank.

If you need to add or subtract two rational expressions, how would you do it

figure the common denominator. Then, using that, add/subtract the values:
1/3 + 3/7
21 = 3*7, so you really have
(1*7)/(3*7) + (3*3)/(3*7) = (7+9)/21 = 16/21 
a barrel can be filled in1 hr by 6 taps how long will it take to fill the barrel with 4 taps