You randomly select one card from a 52-card deck. Find the probability of selecting a red ten or a red jack.

解

Y o u r an d o m l y se l ec t o n e c a r d f ro m a 52 - c a r d d ec k . F in d t h e p ro babi l i t y o f se l ec t in g a re d t e n or a re d ja c k .

\frac{1}{13}

十進法表記

0.07692 \dots

解答ステップ

Find the probability of getting red 10 :

\frac{1}{26}

Find the probability of getting red jack :

\frac{1}{26}

Since the events are disjoint, Use the formula

P (X_{1} \lor X_{2} \lor \dots \lor X_{k}) = P (X_{1}) + P (X_{2}) + \dots + P (X_{k})

= \frac{1}{26} + \frac{1}{26}

\frac{1}{26} + \frac{1}{26} = \frac{1}{13}

= \frac{1}{13}