Question

Cards with number $2$ to $101$ are placed in a box. A card is selected at random.
Find the probability that the card is
divisible by $8$ or $9$.

Answer 1

Multiplies of $8:$ $8,16,\dots \dots .96$ As $\frac{98}{8}=12$ $\Rightarrow \left(12\right)$

Multiplies of $9:$ $9,18,\dots ...99$ As $\frac{99}{9}=11\Rightarrow \left(11\right)$

And a common multiple, $72$

$\Rightarrow$ Total multiples of $8,9=12+11-1=22$

Total cards $=100$

$\Rightarrow$ Probability $=\frac{22}{100}=\frac{11}{50}$.