Envision Math 2.0: Grade 8, Volume 1
EM
Envision Math 2.0: Grade 8, Volume 1 View details
Review

Exercise 1 Page 150

Recall the formula for speed.

Train A

Practice makes perfect

We are told that two trains, A and B, are traveling at a constant rate. We are asked to determine which train is traveling at a faster rate. First, let's calculate the rate of Train A.

Train A

The relationship between the time and distance of Train A is given to us in a table.

Time (hr) 2 3 4 5 6
Distance (mi) 50 75 100 125 150
The constant rate at which Train A is traveling is its speed. Let's recall the formula for speed.

Speed=Distance/Time To find the speed of Train A, we can take any pair of times and distances from the table and plug it into the formula.

Time (hr) 2 3 4 5 6
Distance (mi) 50 75 100 125 150
Speed=Distance/Time 50/2= 25 75/3= 25 100/4= 25 125/5= 25 150/6= 25

We can see that the speed of Train A is 25 miles per hour. Now, let's calculate the speed of Train B.

Train B

Observing Train B's graph of distance and time, we can see that the line passes through the point (1,20).

This means that the train traveled 20 miles in 1 hour. Also, we know that the speed of Train B is constant. Therefore, we can say that the speed of Train B is 20 miles per hour.

Comparison

We found the rate at which each train is traveling.

Train Speed (mph)
Train A 25
Train B 20

Train A is going at a faster rate than Train B.