Question

One side of a roof is in the shape of a trapezoid (similar to the one on Pizza Hut). The top row requires 10 shingles, the second row requires 16 shingles, the third row requires 22, etc. The nth row on the bottom requires 6n + 4 shingles. What is the total number of shingles needed to cover this side of the roof ?
A) n2 + 6n
b) 3n2 + 7n
C) 6n2 + 10
D) 6n2 + 14n

Answer 1

It would depend on the number of rows?

This is an arithmetic sequence and the sum of n terms is --> n/2(2a+(n-1)d), where a is the first term and d is the common difference. In this case a = 10, d =6

n/2(20+6(n-1)) = 3n^2 + 7n = ANSWER

n = number of rows