Respuesta :
If the first term is 20 and the common difference is 2. Then the total number of seats in all 20th rows will be 780 seats.
What are sequence and series?
A sequence is a list of elements that have been ordered in a sequential manner, such that members come either before or after. A series is a sum of sequence terms. That is, it is a list of numbers with adding operations between them.
Your school's auditorium has 20 rows of seats. There are 20 seats in the first row, 22 seats in the second row, 24 seats in the third row, and so on.
The first term is 20 and the common difference is 2.
Then the number of the seats in 20th row will be
[tex]\rm T_n = a + (n - 1)d[/tex]
Then we have
T₂₀ = 20 + (20 - 1)2
T₂₀ = 58
Then the total number of the seats in all 20th rows will be
[tex]\rm S_n = \dfrac{n}{2} (a + T_n)[/tex]
Then we have
S₂₀ = 20 / 2 (20 + 58)
S₂₀ = 10 x 78
S₂₀ = 780 seats
More about the sequence and the series link is given below.
https://brainly.com/question/10813422
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