Question

Find the missing number.

$1,3,7,15,31,63,127,....$

• A. $250$
• B. $150$
• C. $225$
• D. $255$

Answer 1

The correct option is D $255$

Pattern followed by the given numbers is:

$2^1$$-1=1$

$2^2$$-1=3$

$2^3$$-1=7$

$2^4$$-1=15$

$2^5$$-1=31$

$2^6$$-1=63$

$2^7$$-1=127$

Similarly,

$2^8$$-1=255$

Hence, the answer is $255$.