A high speed train travels 80 miles per hour between Paris a

A high speed train travels 80 miles per hour between Paris and St. Cloud. A commuter train, traveling at 64 miles per hour, takes two hours longer for the same trip. How far apart are Paris and St. Cloud?

Solution

Draw the picture of the trains going in the same direction from P to SC.
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Fast train DATA:
rate = 80 mph ; time = x hrs. ; distance = rt = 80x miles
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Commuteer train DATA:
rate = 64 mph ; time = x+2 hrs ; distance = rt = 64(x+2)
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EQUATION:
distance = distance
80x = 64(x+2)
80x = 64x + 128
16x = 128
x = 8 hrs
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Distance from P to SC = 80x = 80*8 = 640 miles