a pair of dice are rolled. given that both dice rolls are less than 5, find the probability that the sum of the rolls is six

解

a p ai r o f d i ce a re ro ll e d . g i v e n t ha t b o t h d i ce ro ll s a re l ess t han 5, f in d t h e p ro babi l i t y t ha t t h e s u m o f t h e ro ll s i s s i x

\frac{5}{36}

十進法表記

0.13888 \dots

解答ステップ

The possible outcomes when two dice are rolled are

6 \cdot 6

Therefore, the number of possible outcomes:

6^{2}

Find the number of favorable outcomes of the sum of the rolls is 6:

5

Probability

= \frac{number of favorable outcomes}{total number of outcomes}

= \frac{5}{6 ^{2}}

6^{2} = 36

= \frac{5}{36}