Answer:
number of action figures = 3 + 6(n-1)
at n = 9: number of action figures = 51
Step-by-step explanation:
first row: 3
second row: 6 more than the row before it (3) = 6 + 3 = 9
third row: 6 + 9 = 15
arithmetic series: , where
is the nth term in the output
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
when the row is 9, the number of action figures is equal to
3 + 6(9-1) = 3 + 6 * 8 = 51