Thread: Setting up an Average mph problem

A certain car increased its average speed by 5 miles per hour in each successive 5-minute interval after the frist interval. If in the first 5-minute interval its average speed was 20 miles per hour, how many miles did the car travel in the third 5-minute interval?

My answer is 30 miles per hour. Based on common sense. Is there a formula someone can show me to set up similar type problems so I will be able to do these problems in an exam. Cheers

Originally Posted by thecapaccino

A certain car increased its average speed by 5 miles per hour in each successive 5-minute interval after the frist interval. If in the first 5-minute interval its average speed was 20 miles per hour, how many miles did the car travel in the third 5-minute interval?

My answer is 30 miles per hour. Based on common sense. Is there a formula someone can show me to set up similar type problems so I will be able to do these problems in an exam. Cheers

The question did not ask how fast the car was going, it asked how many miles it travelled.

In the third interval it was travelling at a speed of 30 mph as you said.
speed = (distance travelled)/time
=> distance = speed * time
=> distance = 30mph * 5min
=> distance = 30mph * 5/60 hours
=> distance = (30 * 5/60) miles
=> distance = 5/2 miles = 2.5 miles

My goodness. Reading is fundamental. Thank you....I must take care to answer the questions in future.