Question Detail
Question
Find the sum of the first 120 terms of the arithmetic progression 5, 7, 9, ...
Correct Answer
Option A is the correct answer.
Detailed Explanation
a=5, d=2, n=120. S_n = n/2[2a+(n−1)d] = 120/2[10+238] = 60×248 = 14,880.
Hint
Use S_n = n/2[2a + (n−1)d].