## College Algebra (10th Edition)

We know that probability$=\frac{\text{number of favorable outcomes}}{\text{number of possible outcomes}}.$ Let $X$ be the cards that contain a number divisible by $5$, thus $X=\{5,10,15,20,25,30,35,40,45,50,55,60,65,70,75,80,85,90,95,100.\}$. Let $S$ be the set of all cards Hence here probability$=\frac{|X|}{|S|}=\frac{20}{100}=0.2.$ Let $Y$ be the cards that contain a $1$ or a prime, thus $Y=\{1,2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97\}$. Hence here probability$=\frac{|Y|}{|S|}=\frac{26}{100}=0.26.$