4.2+Changing+Speeds

__changing speeds__


 * The speed limit on many sections of the interstate highway is 65 miles per hour. If the students had traveled at this speed for the whole trip, it would have taken them less time to get home. However, if they had stopped for a rest and food breaks, they would have probably averaged a slower speed, such as 50 miles per hour.**

__Problem 4.2__


 * a. Make tables of time and distance data, similar to the table you made for problem 4.1,for travel at 50 miles per hour and 65 miles per hour.**


 * time (hours)| |Distance (miles)


 * 1| |50|
 * 2| |100|
 * 3| |150|
 * 4| |200|
 * 5| |250|
 * 6| |300|
 * 7| |350|
 * 8| |400|
 * 9| |450|
 * 10| |500|


 * time (hours)| |Distance (miles)|
 * 1| |65|
 * 2| |130|
 * 3| |195|
 * 4| |260|
 * 5| |325|
 * 6| |390|
 * 7| |455|
 * 8| |520|
 * 9| |585|
 * 10| |650|


 * Plot the data from both tables on one coordinate grid. Use a** **different color for each set of data. Using a third color, add data points for the times and distances traveled at 55 miles per hour (from problem 4.1).

b. How are the tables for the three speeds similar? How are they different?** The three speeds are similar by increasing at the same rate. They are different by some being faster than others.

The three speeds are similar by all being no more than 20 or more units apart. they are different by the size of the numbers.
 * c. How are the graphs for the three speeds similar? How are they different?**

To calculate any speed on a table, start by multiplying the number by 10 and then halve it so you get the multiple of 5. Then you work up.
 * d. 1. look at the table and graph at 65 miles per hour. What pattern of change in the data helps you calculate the distance traveled for any given time? In words, write a rule that explains how to calculate the distance traveled for any given time.**

s*10 halved = 5
 * 2. Use symbols to write your rule as an equation**.
 * E. 1. Now write a rule, in words, that explains how to calculate the distance traveled for any given time when the speed is 50 miles per hour.**