Answer:
33rd term
Explanation:
To get the number of terms of the sequence, we will use the sum of nth term of the sequence formula;
Sn = n/2(a+l)
Tn = a + (n-1)d
a = 5
d = 9-5 = 13-9 = 4
Tn = 5 + (n-1)4
Tn = 5 + 4n-4
Tn = 4n+1
Sn = n/2(5+257)
Sn = 262n/2
Sn = 131n
Sn-1 = 131(n-1)
Sn-1 = 131n-131
Since Tn = Sn - Sn-1
4n + 1 = 131n - 131n + 131
4n + 1 = 131
4n = 131 - 1
4n = 130
n = 130/4
n = 32.5
n ≈ 33
Since n = 32.5 Hence257 occupies the 33rd term in the sequence