Question

The sum of the series 3+5+7+9+...+25 is​

Answer 1

Step-by-step explanation:

a=3 ; d=2

$tn = a + (n - 1)d \\ = > 25 = 3 + 2n - 2 \\ = > 24 = 2n \\ = > n = 12 \\ sn = \frac{n}{2} (a + (n - 1)d) \\ = \frac{12}{2} (1 + 24) \\ =6 \times 25 \\ = 150 \\ sum \: of \: the \: given \: series \: is \: = 150$

hope it helps