Question

A student drives home from college on break. She travels 412 miles in 8 hours. What was the student’s speed in mph? Round to 1 decimal place. If the student wants to return to school in 6 hours, what should her average speed be? Round to 1 decimal place. Her father tells her not to travel back at over 60 mph. If 60 mph is her average speed, how long will it take her to get back to school? Round to 1 decimal place.

Answer 1

• Average peed from college to home in 8 hours = 51.5 mph
• Average peed from home to college in 6 hours = 68.7 mph
• Time taken to reach college at 60mph = 6 hours 52 minutes

Explanation:

Student's speed from college to home

• Distance from college to home = 412 miles
• Time taken to travel this distance = 8 hours
• Average Speed = Distance/Time = 412/8 = 51.5 mph

Student's speed from home to college

• The distance from home to college is assumed to be the same as from college to home

• Distance from home to college = 412 miles
• Time taken for travel = 6 hours
• Average speed = 412/6 = 68.7 mph

Time take to travel from home to college at 60 mph

• Distance = 412 miles
• Average speed = 60 mph
• Time taken = Distance/speed = 412/60 = 6.8666 hours
• Converting to fraction, 412/60 = 6 13/15 hours
• 13/15 hour = 13/15 x 60 minutes = 52 minutes
• So time taken to reach school at 60 mph average speed = 6 hours 52 minutes