Question

Select the number that can come in place of the question mark (?) in the following series: \[ 3,\ 7,\ 15,\ 31,\ 63,\ ? \]

• A. 127
• B. 128
• C. 138
• D. 212

Hint:

When given a number series, check for multiplication or addition patterns. Look for repeated mathematical operations applied to each term.

Answer 1

The Correct Option is A

Let's observe the pattern in the given series:

3 × 2 + 1 = 7
7 × 2 + 1 = 15
15 × 2 + 1 = 31
31 × 2 + 1 = 63
63 × 2 + 1 = 127

Each term is obtained by multiplying the previous term by 2 and then adding 1.

So, the next term is:
63 × 2 + 1 = 126 + 1 = 127

Answer: 127