This 45-minute test has 9 questions worth 20 points on sequences, sigma notation, series sums and applications. Show all work, and round money to the nearest cent unless told otherwise. A calculator is allowed.
- Grade: Algebra 2
- Chapter: Sequences and Series
- Common Core: A-SSE.B.4, F-BF.A.2, F-IF.A.3
- Time: 45 minutes
- Total: 20 points (Question 1: 2 pts; Question 2: 2 pts; Question 3: 2 pts; Question 4: 2 pts; Question 5: 2 pts; Question 6: 2 pts; Question 7: 2 pts; Question 8: 3 pts; Question 9: 3 pts)
Question 1: Sequence from a graph (2 points)
The graph shows the first four terms of a sequence.
- Write an explicit formula for \(a_{n}\). (1 point)
- Find \(a_{30}\). (1 point)
Question 2: Alternating sequence (2 points)
A sequence begins \(6,\,-12,\,24,\,-48\), and each term is found the same way from the one before it.
- Write an explicit formula for \(a_{n}\). (1 point)
- Find \(a_{9}\). (1 point)
Question 3: Recursive to explicit (2 points)
A sequence is defined by \(a_{1}=9,\quad a_{n}=a_{n-1}-4\).
- List the first four terms. (1 point)
- Write an explicit formula and find \(a_{25}\). (1 point)
Question 4: Sigma evaluation (2 points)
Consider \(\sum_{k=1}^{6}(2k+3)\).
- Write out all the terms. (1 point)
- Find the sum. (1 point)
Question 5: Lecture hall (2 points)
A lecture hall has 20 rows. Row 1 has 12 seats and every row has 3 more seats than the row before it.
- How many seats are in row 20? (1 point)
- How many seats are in the hall? (1 point)
Question 6: Series with negative ratio (2 points)
Evaluate \(\sum_{k=1}^{8}3(-2)^{k-1}\).
Question 7: Missing terms (2 points)
A geometric sequence of positive terms has \(a_{4}=24\) and \(a_{6}=96\).
- Find the common ratio and \(a_{1}\). (1 point)
- Find \(a_{8}\). (1 point)
Question 8: Growing deposits (3 points)
Aisha deposits $100 into a savings jar in month 1 and increases the deposit by $15 each month after that. The chart shows the first four months.
- Find her deposit in month 24. (1 point)
- Find the total she has deposited after 24 months. (2 points)
Question 9: Loan amount (3 points)
Liam repays a loan with 24 monthly payments of $400. The interest rate is 0.5% per month, so a payment made \(k\) months from now is worth \(400(1.005)^{-k}\) today. The amount borrowed equals the value today of all 24 payments.
- Write the amount borrowed in sigma notation. (1 point)
- Find the amount borrowed to the nearest cent. (1 point)
- Find the total interest Liam pays. (1 point)
See every chapter on the Algebra 2 math page.



