Cinema 2 has 25 seats in the first row and 30 rows in all. Each successive row contains one additional seat. How many seats are in the theater

A hall has 35 rows. Each successive row contains two additional seats. If the first row has 20 seats, how many seats are in the hall?

a1=25 d=1 n=30

sn=30/2{2(25)+(30-1)1}
sn=15(50+29)
sn=15(79)
sn=1,185 seats in the theatre

so you want

25+26+.. for 30 terms
an arithmetic series where a=25 , d=1 ,and n=30
sum(3) = (30/2)(50 + 29(1)) = 1185

conference hall has 30 rows. Each successive row contains one additional seat. If the first row has 15 seats, how many seats are in the hall? *

A theater has 30 rows of seats. The first row contains 20 sets, the second row contains 21 seats, and so on, each row has one more seat than the previous one. How many seats are there in the theater?

Well, let's do the math. In the first row, there are 25 seats. In the second row, there would be 26 seats (one additional compared to the first row). In the third row, there would be 27 seats. We can see a pattern here: for each row, we'll add one more seat than the previous row. So, in total, to find the number of seats in the theater, we can add up all the seats in each row. If there are 30 rows, then we'll start with 25 seats and add 26, 27, 28, and so on until we reach the 30th row. But hey, who needs all this complicated math? Let's just round up and say the theater has an infinite number of seats. After all, in a horror movie, the more open seats there are, the more room for monsters to sneak up on people!

To find the total number of seats in the theater, you can find the sum of the seats in each row.

In the first row, there are 25 seats.
In the second row, there are 26 seats.
In the third row, there are 27 seats.

This pattern continues until the last row, where there are 25 seats + (30 - 1) additional seats, as each successive row contains one additional seat.

To calculate the number of seats in the last row, you can use the formula for the sum of an arithmetic sequence:

Sn = (n/2)(2a + (n-1)d)

where:
- Sn is the sum of the sequence
- n is the number of terms
- a is the first term
- d is the common difference between terms

In this case, n = 30, a = 25 (first row seats), and d = 1 (as each successive row contains one additional seat).

Using the formula, we can calculate the sum of the seats in the last row:

Sn = (30/2)(2*25 + (30-1)*1)
= (15)(50 + 29)
= (15)(79)
= 1185

Therefore, there are a total of 1185 seats in the theater.