SOLUTION: Marilyn drove her car from Amirillo to Dallas at an average rate of 55 miles per hour and returned over icy roads averaging only 30 miles per hour. Find the time going and the time

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: Marilyn drove her car from Amirillo to Dallas at an average rate of 55 miles per hour and returned over icy roads averaging only 30 miles per hour. Find the time going and the time      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


   



Question 214154: Marilyn drove her car from Amirillo to Dallas at an average rate of 55 miles per hour and returned over icy roads averaging only 30 miles per hour. Find the time going and the time returning if the time returning was 4 hours more than the time going.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
write 1 equation for going
and another for returning
d%5B1%5D+=+r%5B1%5D%2At%5B1%5D
and
d%5B2%5D+=+r%5B2%5D%2At%5B2%5D
given:
r%5B1%5D+=+55 mi/hr
r%5B2%5D+=+30 mi/hr
t%5B2%5D+=+t%5B1%5D+%2B+4 hrs
d%5B1%5D+=+d%5B2%5D (call it d)
---------------------------------
Rewrite the equations
d+=+55t%5B1%5D
d+=+30%2A%28t%5B1%5D+%2B+4%29
55t%5B1%5D+=+30t%5B1%5D+%2B+120
25t%5B1%5D+=+120
t%5B1%5D+=+4.8 hr
t%5B1%5D+%2B+4+=+8.8 hr
The time going was 4.8 hrs and
the time returning was 8.8 hrs
check answer:
d+=+55t%5B1%5D
d+=+55%2A4.8
d+=+264 mi
d+=+30%2A%28t%5B1%5D+%2B+4%29
d+=+30%2A8.8
d+=+264 mi
OK