Solve the problem.
-A lecture hall has 11 rows of seats. The first row has 15 seats, and each row after that has 4 more seats than the previous row. How many seats are in the last row? How many seats are in the lecture
Hall?
A) last row: 59; total seats: 407
B) last row: 55; total seats: 385
C) last row: 59; total seats: 209
D) last row: 55; total seats: 209

Question

Quizplus · Accepted Answer

The last row has 15 + 4*(11-1) = 55 seats. The total number of seats is the sum of an arithmetic series: 11/2 * (15 + 55) = 385.

Solve the Problem. -A Lecture Hall Has 11 Rows of Seats. the First