ExplanationTo calculate Svetlana’s speed during the second half of the race, first calculate how long it took her to run the first half of the race. Svetlana ran the first 5 kilometers at a constant rate of 12 kilometers per hour.
These values can be used in the D = RT formula:
D(km)=R(km per hour) * T (hr)
Svetlana’s time for the first part of the race is \(\frac{5}{12}\)hours, or 25 minutes.
She completed the entire 10-kilometer race in 55 minutes, so she ran the last 5 kilometers in 55 – 25 = 30 minutes, or 0.5 hours. Now create another chart to find the rate at which she ran the last 5 kilometers:
5 = 0.5r
10 = r
Svetlana ran the second half of the race at a speed of 10 kilometers per hour.
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