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3 hours after starting a trip, a driver increased his speed by 10 mph and arrived at his destination 11 hours after starting his journey. If
Question
3 hours after starting a trip, a driver increased his speed by 10 mph and arrived at his destination 11 hours after starting his journey. If the distance traveled was 894 miles, find the original speed of the driver.
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Mathematics
4 years
2021-07-18T03:21:38+00:00
2021-07-18T03:21:38+00:00 1 Answers
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Answers ( )
Answer:
74 mph
Step-by-step explanation:
The driver started driving at s mph.
After 3 hours, the speed became s + 10 mph.
The total time is 11 hours, so 3 hours were driven at s mph and 8 hours were driven at s + 10 mph.
speed = distance/time
distance = speed * time
distance = (distance driven at speed s) + (distance driven at speed s + 10)
894 = s * 3 + (s + 10) * 8
3s + 8s + 80 = 894
11s + 80 = 894
11s = 814
s = 74
Answer: 74 mph