SOLUTION: An oil tanker can be filled in 10 hours from one pipe. It can be filled by another pipe in 8 hrs. How long will it take to fill the tank if both pipelines are used . answer:

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Question 164479: An oil tanker can be filled in 10 hours from one pipe. It can be filled by another pipe in 8 hrs. How long will it take to fill the tank if both pipelines are used .

answer: it will take 2 11/12 hours to fill the storage tank using both pipes
need a breakdown of how my book got 2 11/12 hours to fill the storage tank using both pipes as the answer
Found 2 solutions by checkley77, ptaylor:
Answer by checkley77(12844) (Show Source):
You can put this solution on YOUR website!
10*8/(10+8)=80/18=4.444 HOURS TO FILL THE TANK USING BOTH PIPES.
BELIEVE YOUR ANSWER OF 2 11/12 IS INCORRECT.

Answer by ptaylor(2198) (Show Source):
You can put this solution on YOUR website!
An oil tanker can be filled in 10 hours from one pipe. It can be filled by another pipe in 8 hrs. How long will it take to fill the tank if both pipelines are used .

Let x=amount of time it takes to fill the tanker when both pipelines are used
First pipe fills at the rate of 1/10 tanker per hour
Another pipe fills at the rate of 1/8 tanker per hour
Together they fill at the rate of 1/10 + 1/8=4/40 +5/40=9/40 tanker per hour.
So our equation to solve is
(9/40)*x=1 ( 1 tanker, that is) multiply each side by 40
9x=40 divide each side by 9
x=4 4/9 hours----------------------------answer
CK
First pipe:
(1/10)*(4 4/9)=(1/10)*(40/9)=4/9 of the tanker
Second pipe:
(1/8)*(40/9)=5/9
4/9 + 5/9=1
9/9=1
1=1
I THINK YOUR BOOK IS WRONG.
Hope this helps---ptaylor