Question

One term in the number series is wrong. Find out the wrong term.

$4,6,15,56,280,1644$

• A. $280$
• B. $1644$
• C. $56$
• D. $15$

Answer 1

The correct option is A $280$

The given series follow a pattern :

$4\times 2-2=6,$

$6\times 3-3=15,$

$15\times 4-4=56,$

$56\times 5-5=275\ne 280,$

$280\times 6-6=1644$.

Hence, $280$ is wrong in the given series.