Question

Fifty tickets are sold for a raffle. You buy 5 tickets, and your friend buys 3 tickets. One ticket is randomly chosen as the winning ticket. What is the probability that you or your friend wins the raffle?

Answer 1

Let:

A = You win the raffle

B = Your friend win the raffle

N = Total number of tickets

a = Number of tickets you bought

b = Number of tickets your friend bought

so:

$\begin{gathered} P(A)=\frac{a}{N}=\frac{5}{50}=\frac{1}{10}=0.1 \\ P(B)=\frac{b}{N}=\frac{3}{50}=0.06 \\ so\colon \\ P(A\cup B)=P(A)+P(B) \\ P(A\cup B)=0.1+0.06=0.16 \end{gathered}$

Answer:

16%