Probability 3847

Out of 20 boys playing football or handball, 16 boys play football, and 9 boys play handball. Determine the percentage probability that, by randomly selecting a boy, he plays:

a) football only;
b) only handball
c) football and handball

Correct answer:

a =  55 %
b =  20 %
c =  25 %

Step-by-step explanation:

$$\begin{gathered} p=16+9-20=5 \\ a=100\cdot 11/20=55\% \end{gathered}$$

$b=100\cdot 4/20=20\%$

$c=100\cdot p/20=100\cdot 5/20=25\%$

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