Mathematics

This is an arithmetic sequence problem where you need to find how many terms sum to a target value. The key insight is recognizing that the seat counts form a linear pattern (20, 22, 24, …), then using the arithmetic series sum formula $S_n = \frac{n}{2}(a_1 + a_n)$ or $S_n = \frac{n}{2}(2a_1 + (n-1)d)$ to set up an equation for $n$. Once you have the equation, solve the resulting quadratic to find the number of rows.

This is an arithmetic sequence problem where you need to find how many terms sum to a target value. The key insight is recognizing that the seat counts form a linear pattern (20, 22, 24, …), then using the arithmetic series sum formula $S_n = \frac{n}{2}(a_1 + a_n)$ or $S_n = \frac{n}{2}(2a_1 + (n-1)d)$ to set up an equation for $n$. Once you have the equation, solve the resulting quadratic to find the number of rows.