Suppose that you deposit into a savings account one cent on January 1, five cents on January 2, twenty five cents on January 3, and so on, quintupling the amount of your deposit each day. What is the first day that your daily deposit will exceed $10,000?
A) January 6
B) January 7
C) January 8
D) January 9

Question

Quizplus · Accepted Answer

The deposit amount follows a geometric progression with the first term as $0.01 and a common ratio of 5. The formula for the nth term is $ a_n = 0.01 \times 5^{(n-1)} $. Solving for $ a_n > 10000 $, we find that on January 9 (n=9), the deposit exceeds $10,000.

Suppose That You Deposit into a Savings Account One Cent