Solve the problem.
-A brick staircase has a total of 19 steps The bottom step requires 141 bricks. Each successive step requires 5 less bricks than the prior one. How many bricks are required to build the staircase?
A) 3,534 bricks
B) 1,776.5 bricks
C) 1,824 bricks
D) 3,648 bricks

Question

Quizplus · Accepted Answer

The number of bricks required forms an arithmetic sequence with the first term $a = 141$, common difference $d = -5$, and number of terms $n = 19$. The sum of an arithmetic series is given by $S_n = \frac{n}{2}[2a + (n-1)d]$. Substituting the given values, $S_{19} = \frac{19}{2}[2(141) + (19-1)(-5)] = \frac{19}{2}[282 - 90] = \frac{19}{2}[192] = 1824$ bricks.

Solve the Problem. -A Brick Staircase Has a Total of 19 Steps the 19