Question

A pair of dice is thrown. Find the probability of getting a sum of 9 or more if 4 appears on the first die.

• A. $\frac{2}{18}$
• B. $\frac{1}{17}$
• C. $\frac{1}{18}$
• D. $\frac{1}{16}$

Answer 1

Answer: (C)

Total possible outcomes $n(\mathrm{s})=6\times 6=36$
Favourable cases where the sum is 9 or more with 4 on the $1^{\text{st }}$ die $=[(4,5),(4,6)]$
Event of getting the sum 9 or more with 4 on the $1^{\text{st }}$ die $=n(E)=2$
Probability of getting a sum of 10 or more with 4 on the $1^{\text{st }}$ die $=\frac{n(E)}{n(S)}=\frac{2}{36}=\frac{1}{18}$