How many terms of progression 3, 5, 7, 9, . . . . . must be taken in order that their sum will be 2600? Click to Show/Hide Solution \[ S_n = \frac{n}{2}[2a_1 + (n - 1) d] \] \[ 2600 = \frac{n}{2}[2(3) + (n - 1) (2)] \] \[ n =50 \leftarrow \text{answer} \]