A pair of dice is rolled. Find the probability of rolling a sum not more than 9

解

A p ai r o f d i ce i s ro ll e d . F in d t h e p ro babi l i t y o f ro ll in g a s u m n o t m ore t han 9

\frac{5}{6}

十進法表記

0.83333 \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 rolling a sum no more than 9:

30

Probability

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

= \frac{30}{6 ^{2}}

\frac{30}{6 ^{2}} = \frac{5}{6}

= \frac{5}{6}