Question

Two dice are thrown simultaneously. The probability obtaining a total score less than 11 is $1-\frac{1}{n(n+1)}$.Find $n$

Answer 1

Probability of scoring total of 11 or 12 is $\frac{3}{36}=\frac{1}{12}$
Therefore required probability $=1-\frac{1}{12}=1-\frac{1}{3\times 4}$
$\therefore n=3$