Question

david drove 70 miles in the first 1.75 hours of his trip. how much longer should it take him to drive an additional 120 miles if he drives at the same average speed?

Answer 1

3 hours

Explanation:

Since the speed is remaining the same, time is proportional to distance, so you have ...

1.75 hours/(70 miles) = (additional hours)/(120 miles)

Multiply by 120 to find the additional hours:

additional hours = (120/70)·(1.75 hours) = 3 hours

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Units of miles cancel from numerator and denominator of (120 miles)/(70 miles).