Maggie is training for the croos country meet. On the first day she runs 500m. Each day that she runs 250m more than the day before. At this rate Maggie thinks she can reach her goal of 5km in a single day on the 21stcday. Her sister says she will match the goal on the 19th day

Sister is correct.

Step-by-step explanation:

Given:

Starting distance a = 500 m

Extend ever day d = 250 m

Final distance = 5 km = 5,000 m

Find:

Number of days n

Computation:

An = a + (n-1)d

5,000 = 500 + (n-1)250

n = 19 days

Number of days n = 19 days

Sister is correct.

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step-by-step explanation:

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