Question

Which of the following options will continue the given series?
$3$, $?$, $15$, $31$, $63$, $127$

• A. $5$
• B. $7$
• C. $10$
• D. $12$

Answer 1

Answer: (B)

$7$

According to the problem:

Let is each number in the series is the preceeding number

multiplies by $2$ and then increased by $1$

Thus, $\left(3\times 2\right)+1=?$

$\left(7\times 2\right)+1=15$

$\left(15\times 2\right)+1=31$ so on

Missing number is

$\left(3\times 2\right)+1=7$