請教GWD25-21

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Reid took 1 hour to cycle from his home to his college. The graph shows Reed’s distance from his college during that hour. Reid’s average speed for the last 15 minutes of the hour was how many kilometers per hour greater than his average speed for the first 45 minutes?

A .3

B. 4

C. 5

D. 6

E.7

Answer: C

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