Directions for Questions 36 - 40: What will come in place of the question mark (?) in the given series?
7, 5, 7, 17, 63, ?
308
302
309
390
409
Solution
$\begin{align}
& 7\times 1-2=5 \\
& 5\times 2-3=7 \\
& 7\times 3-4=17 \\
& 17\times 4-5=63 \\
& 63\times 5-6=309 \\
\end{align}$