The sum of even numbers between 1 and 31 is:

Answer: Option C

Let S_n = (2 + 4 + 6 + ..... + 30). This is an A.P. in which a = 2, d = 2 and l = 30
Let the number of terms be n Then,
a + (n - 1)d = 30
⇒ 2 + (n - 1) x 2 = 30
⇒ n = 15
$$\begin{array}{rl}& \therefore S_n=\frac{n}{2}\left(a+I\right)\\ & =\frac{15}{2}\times \left(2+30\right)\\ & =15\times 16\\ & =240\end{array}$$