Easy
Find the sum of the first 19 terms of the AP with first term 5 and common difference 2.
Explanation
Explanation
The sum of the first n terms of an AP is Sₙ = n/2 × [2a + (n-1)d]. Here n = 19, a = 5, d = 2. So S = 19/2 × [2(5) + (19-1)(2)] = 19/2 × [10 + 36] = 19/2 × 46 = 437.
PRO TIP
Re-check your working by substituting the answer back into the original question.