a pair of dice is rolled what is the probability of a sum less than 9

解

a p ai r o f d i ce i s ro ll e d w ha t i s t h e p ro babi l i t y o f a s u m l ess t han 9

\frac{13}{18}

十進法表記

0.72222 \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 a sum less than 9:

26

Probability

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

= \frac{26}{6 ^{2}}

\frac{26}{6 ^{2}} = \frac{13}{18}

= \frac{13}{18}