An ordinary 52-card deck is thoroughly shuffled. You are dealt four cards. (a) What is the probability that all four cards are sevens. (b) What is the probability that at least one of the cards is a seven. (c) What is the probability that none of them are seven. (d) What is the probability that two out the four cards is a seven

Respuesta :

Answer:

a) The probability of getting a seven is 4/52

b) At least one of the cards is a seven=0.2813

c) The probability that none of them are seven=  0.7187

d) The probability that two out the four cards is a seven= 0.043

Step-by-step explanation:

A deck contains 52 cards containing 4 sets of 13 cards . Each set has a seven card in it. Thus there are 4 seven cards in a deck of 52 cards.

a) The probability of getting a seven is 4/52=0.0769

b) At least one of the cards is a seven=

1- P(no seven)

= 1- 4C0 * 48C4/ 52C4= 1- 0.7187= 0.2813

c) The probability that none of them are seven=4C0 * 48C4/ 52C4=  0.7187

d) The probability that two out the four cards is a seven= First card is seven * second Card is seven * two cards are not seven

= 4/52* 3/51*48/50= 0.0769*0.0588*0.96= 0.043