Question

A box contains cards number from $1$ to $20$. A cards is drawn at random from the box. Find probability that number on the drawn card is
A number divisible by $3$

Answer 1

Number of possible outcomes$=20$

Composite numbers$=\{3,6,9,12,15,18\}=11$

$P\left(anumberdivisibleby3\right)=\frac{6}{20}=\frac{3}{10}$

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