An express train and a local train both leave GraySolutionEx

An express train and a local train both leave Gray

Solution

Express DATA:
distance = 60 miles ; rate = 2x mph ; time = d/r = 60/2x = 30/x hr.
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Local DATA:
distance = 60 miles ; rate = x mph ; time = 60/x hr.
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Equation:
local train time - express train time = 2 hrs
60/x - 30/x = 2
60 - 30 = 2x
2x = 30
x = 15 mph (local train speed)
2x = 30 mph (express train speed)