Find the sum of 24 terms of the list of numbers whose nth term is given by: $a_n=3+2n$ |
200 172 672 408 |
672 |
The correct answer is Option (3) → 672 We are asked to find the sum of 24 terms of the sequence: $a_n = 3 + 2n$ Step 1: First term ($a_1$) and 24th term ($a_{24}$) $a_1 = 3 + 2(1) = 5$ $a_{24} = 3 + 2(24) = 3 + 48 = 51$ Step 2: Sum of first n terms of an arithmetic progression Formula: $S_n = \frac{n}{2} (a_1 + a_n)$ $S_{24} = \frac{24}{2} (5 + 51) = 12 \times 56 = 672$ |