Question

A card is drawn at random from a well-shuffled deck of playing cards. Find the probability that the card drawn is a card of spade or an ace.

Answer 1

Let S be the sample space of drawing a card from a well-shuffled deck.

n(S) = `""^52C_1`

= 52

There are 13 spade cards and 4 aces in a deck. As the ace of spades is included in 13 spade cards, so there are 13 spade cards and 3 aces

A card of spades or an ace can be drawn in

`""^13C_1 + ""^3C_1 = 13 + 3`

= 16

Probability of drawing a card of a spade or an ace = `16/52`

= `4/13`