Question 1186524
A concert room has spaces for 10 seats in the first row, 13 in the second, 16 in the third, and so on.

a. If there are 20 rows in the theater, represent the total number of seats in the concert room in sigma notation.
b. What is the maximum number of seats that can be occupied in the said concert room?
<pre>Formula for the SUM of an AP: {{{matrix(1,3, S[n], "=", (n/2)(2a[1] + (n - 1)d))}}}, with {{{matrix(3,3, n, "=", 20, a[1], "=", 10, d, "=", 3)}}}
 {{{matrix(1,3, S[n], "=", (n/2)(2a[1] + (n - 1)d))}}} then becomes: {{{matrix(3,3, S[20], "=", (20/2)(2(10) + (20 - 1)3), S[20], "=", 10(20 + 19(3)), S[20], "=", 10(20 + 57))}}}
Maximum number of seats with 20 rows, or {{{highlight_green(matrix(1,5, S[20], "=", 10(77), "=", 770))}}}