Solve the problem.
-As part of her retirement savings plan, Patricia deposited $350 in a bank account during her first year in the workforce. During each subsequent year, she deposited $50 more than the previous year. Find how much she deposited during her twentieth year in the workforce. Find the total amount deposited in the twenty years.
A) $1300; $33,000
B) $1350; $17,000
C) $1300; $16,500
D) $1350; $34,000

Question

Quizplus · Accepted Answer

During her twentieth year, Patricia deposited $1300, calculated as the initial $350 plus 19 years of adding $50 ($350 + $50*19 = $1300). The total amount deposited over 20 years is a sum of an arithmetic series with the first term $350, the common difference $50, and 20 terms. The sum is $16,500, calculated using the formula for the sum of an arithmetic series: $S_n = \frac{n}{2}[2a + (n-1)d]$, where $n=20$, $a=350$, and $d=50$.

Solve the Problem. -As Part of Her Retirement Savings Plan, Patricia Deposited $350