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Here Is The Problem.

Julia drove from her home to her aunt's house in 3 hours and 30 minutes. The distance between the houses is 175 miles. Knowing that distance = rate X time, find that car's average speed.

Answer d = 175 mph t = 3 1/2, then 175 mph = r X 3 1/2 hr. Solving for rate(r), we get r = 50 mph.

This was an example. I am looking for an explanation of how this is true.

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1 Answer

Do you understand the equation d = r * t?

Solving for rate, we get r = d / t

Do you understand that we are trying to get a measure of how much distance we traveled per some unit of time?

If I travel a distance of 100 miles and I drove for 2 hours, what rate must I have I been traveling?

r = 100 mph / 2 hours = 50 miles/hour (mph).

Is this easier to follow than your example?

Work it the other way.

What if I say, I drive 50 mph and I drive for two hours.

What distance did I travel?

d = r * t = (50 m/h) * ( 2 h) = 100 miles.

Does that help?

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