Issac drove the first three hours at 44 miles per hour.
Step-by-step explanation:
Given,
Average speed of Isaac = 49 mph
Let,
x be the speed during last three hours.
Speed during first three hours = 4x-172
Average =
Multiplying both sides by 2
Dividing both sides by 5
Speed during last three hours = x = 54 mph
Speed during first three hours = 4x-172 = 4(54)-172 = 216-172 = 44 mph
Issac drove the first three hours at 44 miles per hour.
Keywords: average, division
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