Thread: Fractional Equation? Confused...need some assurance

1. Fractional Equation? Confused...need some assurance

Pipes A and B can fill a storage tank in 8 hours and 12 hours, respectively. With the tank empty, pipe A was turned on at noon, and then pipe B was turned on at 1:30pm. At what time was the tank full?

How do I solve this??

x= ???
I got x/8 = amount of the tank filled using A
x/12 = amount of tank filled using B

maybe 1.5x/8 + x/12 = 1 ?

2. Originally Posted by Dunit0001
Pipes A and B can fill a storage tank in 8 hours and 12 hours, respectively. With the tank empty, pipe A was turned on at noon, and then pipe B was turned on at 1:30pm. At what time was the tank full?

How do I solve this??

x= ???
I got x/8 = amount of the tank filled using A
x/12 = amount of tank filled using B

maybe 1.5x/8 + x/12 = 1 ?
Pipe A fill the tank at a rate of 1/8 of a tank per hour

Pipe B fills the tank at a rate of 1/12 of a tank per hour.

At 1:30 pipe A has been running for 1.5 hours and so the tank is (1.5)/8
full.

Now suppose it takes a further x hours to fill the tank, then we have an
additional x/8 of a tank added from A and x/12 of a tank from B. Hence as
the tank is now full we have:

(1.5)/8 + x/8 + x/12 = 1

Now solve this for x to find how many hours after 1:30 the tank is full, and
so the time at which it is full.

RonL