erza is training for a track race. He starts by sprinting 100 yards. he gradually increases his distance, adding 5 yards a day for 21 days. Which explicit formula models this situation? A. an=100 + (n-1)21 B. an=100 + (n-1)5 C. an=5 + (n-1)100 D. an=21 + (n-1)5

Option B.

Step-by-step explanation:

It is given that erza is training for a track race. He starts by sprinting 100 yards. he gradually increases his distance, adding 5 yards a day for 21 days.  So, the required sequence is

100, 105, 110, 115, ...

It is an AP. Here,

First term = 100

Common difference = 5

Explicit formula for an AP is

where, is first term and d is common difference of the AP.

Substitute in the above formula.

Therefore, the required explicit formula is .

Hence, option B is correct.

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step-by-step explanation: