Answer:
330.
Step-by-step explanation:
Count all the way up. The first row is 20, then goes, 22,24,26,28,30,32,34,36,38,40. These are the number of seats for all 12 rows, since we added 2 each row. Add them all together including 20 to get 330 seats. The whole auditorium has 330 seats.
Hope this helps!
As per arithmetic Progression, there are 372 seats in the given auditorium.
"Arithmetic Progression is a sequence of numbers in order, in which the difference between any two consecutive numbers is a constant value."
Given, the auditorium has 20 seats in the first row.
Then, each successive row contains 2.
We can assume it as an arithmetic progression.
Here, the first term(a) is 20.
The common difference(d) is 2.
Total number of terms(n) is 12.
Therefore, the sum of all the terms is
[tex]= \frac{n}{2}[2a + (n-1)d]\\= \frac{12}{2}[2(20) + (12-1)2]\\= 6[40+(11)2)]\\= 6(40+22)\\= 6(62)\\= 372[/tex]
Learn more about an arithmetic progression here: https://brainly.com/question/20733446
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