Question

omar ordered his sister a birthday card from a company that randomly selects a card from their inventory. the company has 21 total cards in inventory. 14 of those cards are birthday cards. what is the probability that the card chosen is not a birthday card? p(not a birthday card) =

Explanation:

Step1: Find number of non - birthday cards

The total number of cards is 21 and the number of birthday cards is 14. So the number of non - birthday cards is $21 - 14=7$.

Step2: Calculate the probability

The probability formula is $P(A)=\frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}}$. Here, the number of favorable outcomes (non - birthday cards) is 7 and the total number of outcomes (total cards) is 21. So $P(\text{Not a birthday card})=\frac{7}{21}=\frac{1}{3}$.

Answer:

$\frac{1}{3}$