Carissa is budgeting for her next semester at college. she spent $50 on gas this month. economists are predicting gas prices to rise 8% per month for the next 6 months. how much should she budget for gas if classes start next month and are 4 months long?

the answer is d.243.33
(i looked up the question and couldnt find it so i thought i'd post it for anyone who needed it)

Spent on gas this month = $50.

Predicted spent of gas next month = $50 * 1.08

Predicted spent of gases for the four months:

$50 * 1.08
$50 * 1.08^2
$50 * 1.08^3
$50 * 1.08^4

Total spent for the four months:  $50 (1.08 + 1.08^2 + 1.08^3 + 1.08^4) = $50 * (4.8666) = $243.33, which is the option D. 243.33

In all honesty, there really is no “work” per say to show. mainly it’s just using the process of elimination. the question is asking which domain(s) would be the most appropriate for the function c(n). n is the number of observed vehicles so right away, 1, 2, and 3 can be eliminated.why? 1, 2 start in the negatives and therefore it is impossible to observe negative cars. so, #4 would be the best answer to the given problem.