Problema Solution
John and William leave their home traveling in opposite directions on a straight road. John drives 20 miles per hour faster than William. After 4 hours they are 250 miles apart. Find their rates.
Answer provided by our tutors
a. Define a variable for John's rate: x mph
Write an expression for William's rate: x-20 mph
b. Write and solve an equation to find John's rate. Then find William's rate.
They are separating at the rate of x + x-20 = 2x-20 mph.
time*rate = distance
4(2x-20) = 250 miles
8x-80 = 250
8x = 330 miles
x = 41.25
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William's rate = x-20 = 21.25 mph