SOLUTION: Starting at 1 PM, Claude drove the first 27km of his bus route at 15 km/h. How fast must he drive the last 30 km of the route (on the average) in order to arrive at his final stop

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: Starting at 1 PM, Claude drove the first 27km of his bus route at 15 km/h. How fast must he drive the last 30 km of the route (on the average) in order to arrive at his final stop       Log On

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Question 888597: Starting at 1 PM, Claude drove the first 27km of his bus route at 15 km/h. How fast must he drive the last 30 km of the route (on the average) in order to arrive at his final stop by 4 PM?
I was thinking - 15 + x = 57 , but that makes no sense. The answer is at least 25km/h. And that's not even close to what I got.. :/ Thanks!

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
His time for the first +278+ km was:
+27+=+15%2At+
+t+=+27%2F15+
+t+=+1.8+ hrs
From 1 PM to 4 PM is +3+ hrs
He has +3+-+1.8+=+1.2+ hrs to get to his final stop
-----------------
Let +s+ = the speed he needs for last +30+ km
+30+=+s%2A1.2+
+s+=+30%2F1.2+
+s+=+25+ km/hr