We are choosing 2
2
r
shoes. How many ways are there to avoid a pair? The pairs represented in our sample can be chosen in (2)
(
n
2
r
)
ways. From each chosen pair, we can choose the left shoe or the right shoe. There are 22
2
2
r
ways to do this. So of the (22)
(
2
n
2
r
)
equally likely ways to choose 2
2
r
shoes, (2)22
(
n
2
r
)
2
2
r
are "favourable."
Another way: A perhaps more natural way to attack the problem is to imagine choosing the shoes one at a time. The probability that the second shoe chosen does not match the first is 2−22−1
2
n
−
2
2
n
−
1
. Given that this has happened, the probability the next shoe does not match either of the first two is 2−42−2
2
n
−
4
2
n
−
2
. Given that there is no match so far, the probability the next shoe does not match any of the first three is 2−62−3
2
n
−
6
2
n
−
3
. Continue. We get a product, which looks a little nicer if we start it with the term 22
2
n
2
n
. So an answer is
22⋅2−22−1⋅2−42−2⋅2−62−3⋯2−4+22−2+1.
2
n
2
n
⋅
2
n
−
2
2
n
−
1
⋅
2
n
−
4
2
n
−
2
⋅
2
n
−
6
2
n
−
3
⋯
2
n
−
4
r
+
2
2
n
−
2
r
+
1
.
This can be expressed more compactly in various ways.
Answer:
50/50. there is no outside force that decides otherwise
Without context, I can only assume that<em> e</em> is a variable, which means that it is an unknown number. Any letter can be a variable, and you solve for that variable by isolating it on one side of the equation. Example: e = 12
The type of numbers, rational and irrational from the numbers Keisha writes are;
a. Rational numbers; -9, 3.0, 2, and 2.42
b. Irrational numbers; √8
<h3>What is the difference between rational and irrational numbers?</h3>
Rational numbers are numbers are numbers that can be expressed as a ratio of two whole numbers P/Q, in which, <em>Q </em>≠ 0
Irrational numbers are those that cannot be expressed as a fraction P/Q
The given numbers are;
-9, √8, 3.0, 2, 2.42
- √8 = 2•√2 (√2 cannot be expressed as a fraction of two whole numbers)
a. The rational numbers are therefore;
b. The irrational number is; √8
Learn more about rational and irrational numbers here:
brainly.com/question/43641
#SPJ1
Answer:
43
Step-by-step explanation:
