Question

Becca and Kimberly are running at a constant speed in a marathon. Becca runs at 4.5 miles per hour. Kimberly’s progress is shown in the table.
Part A: Who runs faster?

Part B: If Becca and Kimberly are 5 hours into a marathon, how far has each run?

Answer 1

Answer:

Part A: Kimberly

Part B:

Becca = 22.5 miles, Kimberly = 25 miles

Step-by-step explanation:

Part A:

Given that Becca runs at a constant speed of 4.5 miles per hour, use the table to find the constant speed that Kimberly runs, and compare who runs faster.

Let x = time

y = distance

k = speed = y/x

Equation for each person can be written as: y = kx

Therefore:

✔️Equation for Becca if k = 4.5

y = 4.5x

✔️Find k (speed) of Kimberly using (2, 10):

Speed (k) = y/x

k = 10/2

k = 5 miles per hour

Equation for Kimberly would be:

y = 5x

Comparing their speed, Kimberly runs faster because she covers more miles per hour than Becca does.

Part B:

For Becca, substitute x = 5 into Becca's equation, y = 4.5x

Thus:

y = 4.5*5 = 22.5 miles

For Kimberly, substitute x = 5 into Kimberly's equation, y = 5x

Thus:

y = 5*5 = 25 miles