Find the number of terms in the following series.
15, 25, 35, 45, ............, 125
Show answer & explanation
Correct answer: C
Explanation
Series = 15, 25, 35, 45, .........., 125
Number of terms in the AP:
n = (Last term − First term) / Common difference + 1
First term (a) = 15
Common difference (d) = 25 − 15 = 10
Last term (l) = 125
n = (125 − 15) / 10 + 1
= 110 / 10 + 1
= 11 + 1 = 12 terms