Question

Papa drove at an average speed of 30 mph to the airport. He boarded a helicopter and travel at 60 mph to the corporate office. The entire distance was 150 miles and took 3 hours. what was he distance from the airport to the office?

Answer 1

`120` miles

Explanation:

I initially found this by guessing:

What if he spent an hour driving to the airport then two hours flying?

He would then travel `30` miles in the first hour and `2 xx 60 = 120` miles in the next two hours.

That all adds up since he would travel a total of `30 + 120 = 150` miles in a total of `1 + 2 = 3` hours, as required by the question.

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How would you calculate this without guessing?

If he spent all `3` hours driving at an average speed of `30` miles per hour, he would cover `3 xx 30 = 90` miles.

That would be `150 - 90 = 60` miles too short.

The helicopter travels an additional `60 - 30 = 30` miles per hour compared with the car.

So the helicopter portion of the journey must be `60/30 = 2` hours.

In those two hours, the helicopter travels a total of `2 xx 60 = 120` miles, which is therefore the distance between the airport and the office.