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Loretta and her family are going on vacation. Their destination is 610 miles from their home. Loretta is going to share some of the driving with her dad. Her average speed while driving is 55 mph and her dad's average speed while driving is 65 mph. The plan is for Loretta to drive for this first 4 hours of the trip and her dad to drive for the remainder of the trip

Respuesta :

Loretta:
Average driving speed = 55 mph
Time = 4 hours
Distance traveled = 55*4 = 220 miles

Dad:
Average driving speed = 65 mph
Let x =  hours driven
Distance traveled = 65x miles

The length of the trip is 610 miles, therefore
65x + 220 = 610
65x = 390
x = 6  hours

Answer: Loretta's dad drove for 6 hours.