SOLUTION: Two oil pipelines can fill a tank in 30 minutes.Using one of the pipelines would require 45 minutes to fill the tank. How long would it take the second pipeline working alone to fi

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Two oil pipelines can fill a tank in 30 minutes.Using one of the pipelines would require 45 minutes to fill the tank. How long would it take the second pipeline working alone to fi      Log On


   

Question 615249: Two oil pipelines can fill a tank in 30 minutes.Using one of the pipelines would require 45 minutes to fill the tank. How long would it take the second pipeline working alone to fill the tank?
Found 2 solutions by josmiceli, scott8148:
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +t+ = the time in minutes for the 2nd pipeline
to fill the tank
Add their rates of filling to get their rate working together
+1%2F45+%2B+1%2Ft+=+1%2F30+
Multiply both sides by +90t+
+2t+%2B+90+=+3t+
+t+=+90+
The 2nd pipeline takes 90 minutes to fill the tank

Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
in the 30 min it takes to fill together, the 1st pipeline fills 2/3 (30/45) of the tank
___ so the 2nd pipeline fills 1/3 of the tank in 30 min