Question

Find out the wrong number in the series given below :
$31,29,24,22,17,12$

• A. $17$
• B. $12$
• C. $29$
• D. $22$

Answer 1

The correct option is B $12$

$\text{1st term}-\text{2nd term}=31-29=2$
$\text{2nd term}-\text{3rd term}=29-24=5$
$\text{3rd term}-\text{4th term}=24-22=2$
$\text{4th term}-\text{5th term}=22-17=5$
$\text{5th term}-\text{6th term}=17-12=5\ne 2$

The differences are alternately changing between $2$ and $5.$
$\therefore 12$ is wrong.