Students who are solid on rate problems will earn easy points on MathCounts!


The only formula to memorize is the definition of rate, r=\frac{d}{t} where d= distance and t= time.  I find it helpful to draw a quick diagram so I can visualize what is happening to our MathCounts team on their way to and from the contest.  (H=home, MC = MathCounts contest.)

On the return trip we multiply the time by 2, multiply the distance by \frac{3}{2}, and subtract 10 mi/h from the rate.

The first equation I have written derives from the fact that the new rate is equal to the old rate minus 10 mi/h.  Then it is a matter of solving for r=\frac{d}{t} which is the rate to the contest.

Source: MathCounts

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s