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Eleri mows grass in her neighborhood. She charges $35 per yard. Eleri offers a discount to repeat customers, where she charges $3 less than the previous time to cut the grass. Suppose Eleri is cutting your grass for the 8th time. Which explicit formula describes how much she will charge you?

User Varundroid
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2 Answers

4 votes

Final answer:

The explicit formula to calculate Eleri's charge for the 8th grass-cutting service is a8 = 35 + (8 - 1)(-3), which simplifies to a8 = 35 - 21, resulting in a charge of $14.

Step-by-step explanation:

The student's question is about finding an explicit formula for calculating the charge for mowing grass with a discount applied each time.

To find the amount Eleri charges for cutting the grass for the 8th time, we need an arithmetic sequence formula, which typically has the form an = a1 + (n - 1)d, where an is the nth term, a1 is the first term, n is the term number, and d is the common difference between the terms. In this case, the first term a1 is $35, the term number n is 8, and the common difference d is -$3 (because the price decreases by $3 each time).

The explicit formula is a8 = 35 + (8 - 1)(-3), so the charge on the 8th time would be a8 = 35 + 7(-3).

Simplifying that, we get a8 = 35 - 21 = $14. Therefore, Eleri will charge $14 to cut the grass for the 8th time.

User Maksym Fedorov
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3 votes
Minus 3 from 35. Do that eight times. Or simply 8x3=24$. 35-24$=11$. 11$ will be charged
User Iver
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