Question

part 3. solve the problems
show your work for each question.

1. a car travels 120 miles in 2 hours. what is its speed?
2. a runner completes a 400 - meter lap in 50 seconds. what is her speed in meters per second?
3. a train travels 300 miles in 5 hours. what is its average speed?
4. a student walks 3 km to school in 45 minutes. what is her speed in km per minute?
5. a plane flies 1,200 miles in 3 hours. what is its speed?

Explanation:

Step1: Recall speed formula

Speed = $\frac{Distance}{Time}$

Step2: Solve problem 1

For the car, distance $d = 120$ miles and time $t=2$ hours. So speed $v=\frac{120}{2}=60$ miles per hour.

Step3: Solve problem 2

For the runner, distance $d = 400$ meters and time $t = 50$ seconds. So speed $v=\frac{400}{50}=8$ meters per second.

Step4: Solve problem 3

For the train, distance $d = 300$ miles and time $t = 5$ hours. So average - speed $v=\frac{300}{5}=60$ miles per hour.

Step5: Solve problem 4

For the student, distance $d = 3$ km and time $t = 45$ minutes. So speed $v=\frac{3}{45}=\frac{1}{15}$ km per minute.

Step6: Solve problem 5

For the plane, distance $d = 1200$ miles and time $t = 3$ hours. So speed $v=\frac{1200}{3}=400$ miles per hour.

Answer:

1. 60 miles per hour
2. 8 meters per second
3. 60 miles per hour
4. $\frac{1}{15}$ km per minute
5. 400 miles per hour