3.59. An urn contains 5 White Chips, 4 Red Chips and 3 Blue Chips. We will now select 8 chips
with replacement
Let X count the number of
Red Chips
selected. Determine the following:
a)
(
4)
P X
Our variable is how many successes.
.

4
4
8!
4
8
(4!)(4!)
12
12

3.60. An urn contains 5 White Chips, 4 Red Chips and 3 Blue Chips. We will now select chips,
with replacement
until we get a
Blue Chip
. Let X count the number of chips needed to end this experiment. Determine the following:
a)
(
4)
P X
Our variable is how many trials.
,

3
1
3!
9
3
(3!)(0!)
12
12

3.61. An urn contains 5 White Chips, 4 Red Chips and 3 Blue Chips. We will now select chips,
with replacement
until we get a Blue Chip. Determine the following:
a) P(The first
Blue Chip
is selected on the third trial)
Our variable is how many trials.
,