In a theater there are 12 chairs in the first row, each row has 2 more chairs than the previous row, and there are 10 rows. How many chairs are there in the theate
Accepted Solution
A:
Answer: 210Step-by-step explanation:The first term of the sequence, a1, is 12. The common difference, d, is 2. The number of terms is n = 10. The sum is given by the formula ... Sn = (2a1 +d(n-1))(n/2)Filling in the numbers, this is ... S10 = (2·12 +2(10-1))(10/2) = (24+18)(5) = 210There are 210 chairs in the theatre.