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Please help :( Algebra 2 Question

A child arranges toy action figures into rows. The first row has three action figures and each row after the first has six more figures than the row before it. Write a rule for the number of action figures in the nth row. If there are nine , how many action figures are there?

User Pavel Kenarov
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1 Answer

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6 votes

Answer:

number of action figures = 3 + 6(n-1)

at n = 9: number of action figures = 51

Explanation:

first row: 3

second row: 6 more than the row before it (3) = 6 + 3 = 9

third row: 6 + 9 = 15

arithmetic series:
a_n = a_1 + (n-1)d, where


a_n is the nth term in the output


a_1 is the first output

n is the input

d is the difference between terms

here, we are given the row, and we want to figure out the number of action figures. thus, row = input and number of action figures = output.

the first output, in the first row, is 3

the difference between the number of action figures in each row is 6

thus, our formula is


a_n = 3 + (n-1)6 = 3 + 6(n-1)

when the row is 9, the number of action figures is equal to

3 + 6(9-1) = 3 + 6 * 8 = 51

User Slava Ivanov
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