I'm really confused. The formula for calculating distance is d=rXt. However, when using this formula my answers are wrong.

You spot a car traveling 105 miles per hour. How far does it travel in 10 minutes?

D= 105 X .10 my answer: 10.5 miles. However, the correct answer is 17.5 miles

You are traveling 75 miles per hour on the interstate. How long will it take you to travel

15 miles?

15= 75X T

15/75= 0.2 or 20 minutes? However, the correct answer is 12 minutes

How far does a tractor trailer truck traveling 80 miles per hour go in 21 minutes?

D= 80 X .21

16.8 Miles However, the correct answer is 28 miles.

I'm not simply looking for the answer because I already have it. I'm just trying to figure out why I have these questions wrong. Any help would be greatly appreciated. Thanks