Medium
Find the sum of the first 14 terms of the AP with first term 8 and common difference 6.
Explanation
Explanation
The sum of the first n terms of an AP is Sₙ = n/2 × [2a + (n-1)d]. Here n = 14, a = 8, d = 6. So S = 14/2 × [2(8) + (14-1)(6)] = 14/2 × [16 + 78] = 14/2 × 94 = 658.
PRO TIP
Re-check your working by substituting the answer back into the original question.