Question

Christy went jogging on Saturday. The table shows how far she had jogged after various time

S Distance (miles)
Time (hours)
10
2
15
3
20
ST400253
Christy subtracted to find her jogging rate for each time period and said that her rate
increased each hour, from 8 to 12 to 16 miles per hour.
Is Christy correct? Explain why or why not.

Answer 1

Christie is wrong

She should be dividing the distance by the time taken, not subtracting

Explanation:

The jogging rate in miles per hour is given by distance run ÷ time taken
For the first 10 miles it took 2 hours so her rate was 10/2 = 5 mph

For the first 15 miles, it took 3 hours so rate = 15/3 = 5mph

For the first 20 miles, it took 4 hours so rate = 20/4 = 5 mph

For every 1 hour Christie ran 5 miles so her average rate was constant at 5mph