Question 1042512
i couldn't find any answer that was one of your selections.
in year 1, she has 17.
in year 2, she has 17 + 4 * 17 = 5 * 17 = 85
in year 3, she has 85 + 4 * 85 = 5 * 85 = 425
carry this out to year 9 and she has 17 * 5^8 = 6640625.


the key phrase in the problem statement is:
increased by four times the previous year’s population.


that means you take the current year's population and multiply it by 4 and then add it to the current year's population to get the next year's population.


if x in the first year, then it would be x + 4*x in the second year.
x + 4*x is equal to 5*x.


you wind up with a geometric progression where A9 = 17 * 5^8 = 6640625.


the general form of a geometric progression is An = A1 * r^(n-1).