SOLUTION: Benjamin drove for three hours then hit some traffic. He spent the last hour driving 25 miles per hour slower than his average speed on the first part of the trip. Benjamin travele

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: Benjamin drove for three hours then hit some traffic. He spent the last hour driving 25 miles per hour slower than his average speed on the first part of the trip. Benjamin travele      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


   



Question 1092556: Benjamin drove for three hours then hit some traffic. He spent the last hour driving 25 miles per hour slower than his average speed on the first part of the trip. Benjamin traveled a total of 183 miles. How fast was he traveling during the first part of his trip?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +s+ = his speed for the first 3 hrs
+s+-+25+ = his speed for the last hr
Let +d+ = distance in miles travels
during the first 3 hrs
+183+-+d+ = distance trveled in last hr
------------------------------------
(1) +d+=+s%2A3+
(2) +183+-+d+=+%28+s+-+25+%29%2A1+
------------------------------
Substitute (1) into (2)
(2) +183+-+3s+=+s+-+25+
(2) +4s+=+183+%2B+25+
(2) +4s+=+208+
(2) +s+=+52+
His speed was 52 mi/hr for the first 3 hrs
---------------------
check:
(1) +d+=+3%2A52+
(1) +d+=+156+ mi
and
(2) +183+-+d+=+52+-+25+
(2) +d+=+183+-+27+
(2) +d+=+156+ mi
OK