Question

If one ticket is randomly selected from tickets numbered $1$ to $30$. Then find the probability that the number on the ticket is
(i) a multiple of $5$ or $7$
(ii) a multiple of $3$ or $5$

Answer 1

(i) Multiple of 5$\to 5,10,15,20,25,30$

Multiple of 7$\to 7,14,21,28$

Probability of getting multiple of 5 $=\frac{6}{30}=\frac{1}{5}$

Probability of getting multiple of 7 $=\frac{4}{30}=\frac{2}{15}$

(i) Multiple of 3$\to 3,6,9,12,15,18,21,24,27,30$

Multiple of 7$\to 5,10,15,20,25,30$

Probability of getting multiple of 3 $=\frac{10}{30}=\frac{1}{3}$

Probability of getting multiple of 7 $=\frac{5}{30}=\frac{1}{6}$