Question

How many five-card hands (drawn from a standard deck) contain exactly three fives? (A five-card hand is any set of five different cards.)

Answer 1

Answer:

4512.

Step-by-step explanation:

We are asked to find the number of five-card hands (drawn from a standard deck) that contain exactly three fives.

The number of ways, in which 3 fives can be picked out of 4 available fives would be 4C3. The number of ways in which 2 non-five cards can be picked out of the 48 available non-five cards would be 48C2.

$4C3=\frac{4!}{3!(4-3)!}=\frac{4*3!}{3!*1}=4$

$48C2=\frac{48!}{2!(48-2)!}=\frac{48*47*46!}{2*1*46!}=24*47=1128$

We can choose exactly three fives from five-card hands in $4C3*48C3$ ways.

$4C3*48C3=4*1128=4512$

Therefore, 4512 five card hands contain exactly three fives.