Easy
Find the sum of the first 15 terms of the AP with first term 5 and common difference 1.
Explanation
Explanation
The sum of the first n terms of an AP is Sₙ = n/2 × [2a + (n-1)d]. Here n = 15, a = 5, d = 1. So S = 15/2 × [2(5) + (15-1)(1)] = 15/2 × [10 + 14] = 15/2 × 24 = 180.
PRO TIP
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