Question

A standard deck of 52 cards contains 4 suits: hearts, clubs, diamonds, and spades. Each suit consists of cards

numbered 2 through 10, a jack, a queen, a king, and an ace.
Zhi Qing decides to pick one card at random from a standard deck of 52 cards. Let A be the event that she
chooses a three card and B be the event that she chooses a seven card.
What is P(A or B), the probability that the card Zhi Qing chooses is either a three or a seven?

Answer 1

Answer: 2/13

Explanation:

Answer 2

`(2)/(13)`

Explanation:

In probability,

"OR" means "addition"

"AND" means "multiplication"

We want probability of A "OR" B, that means we find each individual probability and "ADD" them.

P(A) means P(choosing a 3 card):

There are 4 three-cards, 1 from each suit, and a total of 52 cards, so

P(A) = 4/52 = 1/13

P(B) means P(choosing a 7 card):

There are 4 seven-cards, 1 from each suit, and a total of 52 cards, so

P(B) = 4/52 = 1/13

Now,

P(A or B) = P(A) + P(B) = 1/13 + 1/13 = 2/13

The answer is
`(2)/(13)`