+123 Problem 1:
The first, second, and the nth terms of an arithmetic sequence are 2, 6, and 58 respectively,
i. Find the value of n
13
ii. For that value of n, find the exact value of the sum of n terms.
(58 + 2) * (13 / 2) = 390
Problem 2:
The seats in a theatre are arranged so that each row accommodates four people more than the previous row. If the first row seats 50 people, how many will the 9th row seat?
+37146 1 an = a1 +(n-1)d a1 = 2 an = 58 d = 4
58 = 2 +(n-1)(4)
14 = n-1
n = 15 For n= 13 a13 = 58-4-4= 50
Sn for arithmetic series = (n (a1+an)/2) = 15 ( 2+58)/2 ) = 450
For a13 sum = n(a1+a13)/2 = 13 (2+50)/2 = 338
