Question

A die is thrown thrice , if the first throw is $5$, then the chance of getting $15$ as the sum is

• A. $\frac{1}{12}$
• B. $\frac{1}{9}$
• C. $\frac{1}{18}$
• D. $\frac{1}{108}$

Answer 1

The correct option is A $\frac{1}{12}$

Total number of ways =$1\times 6\times 6=36$
Favourable outcomes are $(5,4,6),(5,6,4),(5,5,5)$
So, probability of getting $15$ as sum =$\frac{3}{36}=\frac{1}{12}$