Question

1. Which expression calculates the speed in meters per second of an object that travels a distance of 100 m every 20 s?

Answer 1

1. 100 * 20
2. 7 hours
3. 141 kilometers
4. 8.5 hours
5. 55.75 mi/h

Answer 2

Answer:

1. 100/20

2. 7 h

3. 141 km

4. 8.5 hours

5. 56 mi/h

Step-by-step explanation:

(dimensions are omitted)

1. speed = distance/time

speed = 100/20

2. time = distance/speed

time = 315/45 = 7 h

3. distance = speed*time

distance = 35.25 * 4 = 141 km

4. time = distance/speed

to the lake: time = 216/48 = 4.5 h

from the lake: time = 216/54 = 4 h

total time:  4.5 + 4 = 8.5 h

5. speed = distance/time

first trip: speed = 203/3.5 = 58 mi/h

second trip: speed = 243/4.5 = 54 mi/h

average speed = (58 + 54)/2 = 56 mi/h