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

Answer 1

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

Answer 2

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

Answer 3

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?

Answer 4

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?

Answer 5

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? *