Arithmetic Series

Evaluate the arithmetic series described:
2 + (-2) + (-6) + (-10)..., S₁₀

• -160
• -328
• -320
• -336

Find S_n for the given series:
a₁=22
d=-8
n=21

• 1911
• -1449
• -2436
• -1218

• 11

• 9

• 7

• 5

A theater has 32 rows of seats. If there are 26 seats in the 1st row, 30 in the 2nd, 34 in the 3rd, and so on, how many seats are there in all? Assume the pattern continues.

• 2,791 seats

• 2,803 seats

• 2,816 seats

• 2.829 seats

A grocer is creating a display of cans. There are 40 cans on the 1st (bottom) row, 38 cans on the 2nd row, 36 cans on the 3rd row, and so on. How many cans will be on the 15th row?

• 32 cans

• 10 cans

• 12 cans

• 68 cans

• 9

• 10

• 11

• 12

Find the sum of first 20 even numbers.

• 400

• 410

• 420

• 430

You are sitting in row 23 and notice there are 65 seats in your row. The row in front of you has 63 seats and the row behind you has 67 seats. There are 42 rows in the auditorium. How many seats does the auditorium contain? (Hint: Find the number of seats in the first and last rows)

• 2,604
• 2,163
• 2,422
• 2,803

A construction company will be penalized each day of delay in construction for bridge. The penalty will be $4000 for the first day and will increase by $10000 for each following day. How much total money in fines will they pay in 15 days?

A gardener plans to construct a trapezoidal shaped structure in his garden. The longer side of trapezoid needs to start with a row of 97 bricks. Each row must be decreased by 2 bricks on each end  and the construction should stop at 25^th row. How many bricks does he need to buy ?