Please answer this question, and happy valentines day!!

6 friends order lunch. Write an expression that shows the total cost if each person orders one sandwich and one cookie

Svetradugi [14.3K]

1 sandwich + 1 cookie = $x

6 x $X = $6X

5 0

3 years ago

5. Evaluate the function f (x) = 4•7^x for x=-1 and x= 2. Show your work.

mr Goodwill [35]

Answer:

Given

f

(

x

)

=

4

⋅

7

x

For

x

=

−

1

we have

f

(

−

1

)

=

4

⋅

7

−

1

=

4

7

using

a

−

n

=

1

a

n

For x=2, we have

f

(

2

)

=

4

⋅

7

2

=

196

Step-by-step explanation:

5 0

3 years ago

Read 2 more answers

A square garden has a diagonal of 12m. What is the perimeter of the garden? Express in simplest radical form.

FromTheMoon [43]

Answer:

24√2

Step-by-step explanation:

Let the side of the square be x

If the diagonal is 12m (hypotenuse), then;

x^2 + x^2 = 12^2

2x^2 = 144

x^2 = 144/2

x^2 = 72

x = √72

x = √36*2

x = 6√2

Perimeter of the square garden = 4x

Perimeter of the square garden = 4(6√2)

Perimeter of the square garden = 24√2

7 0

3 years ago

A university found that 20% of its students withdraw without completing the introductory statistics course. Assume that 20 stude

EleoNora [17]

Answer:

a) $P(X \leq 2)= P(X=0)+P(X=1)+P(X=2)$

And we can use the probability mass function and we got:

$P(X=0)=(20C0)(0.2)^0 (1-0.2)^{20-0}=0.0115$

$P(X=1)=(20C1)(0.2)^1 (1-0.2)^{20-1}=0.0576$

$P(X=2)=(20C2)(0.2)^2 (1-0.2)^{20-2}=0.1369$

And adding we got:

$P(X \leq 2)=0.0115+0.0576+0.1369 = 0.2061$

b) $P(X=4)=(20C4)(0.2)^4 (1-0.2)^{20-4}=0.2182$

c) $P(X>3) = 1-P(X \leq 3) = 1- [P(X=0)+P(X=1)+P(X=2)+P(X=3)]$

$P(X=0)=(20C0)(0.2)^0 (1-0.2)^{20-0}=0.0115$

$P(X=1)=(20C1)(0.2)^1 (1-0.2)^{20-1}=0.0576$

$P(X=2)=(20C2)(0.2)^2 (1-0.2)^{20-2}=0.1369$

$P(X=3)=(20C3)(0.2)^3 (1-0.2)^{20-3}=0.2054$

And replacing we got:

$P(X>3) = 1-[0.0115+0.0576+0.1369+0.2054]= 1-0.4114= 0.5886$

d) $E(X) = 20*0.2= 4$

Step-by-step explanation:

Previous concepts

The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".

Solution to the problem

Let X the random variable of interest, on this case we now that:

$X \sim Binom(n=20, p=0.2)$

The probability mass function for the Binomial distribution is given as:

$P(X)=(nCx)(p)^x (1-p)^{n-x}$

Where (nCx) means combinatory and it's given by this formula:

$nCx=\frac{n!}{(n-x)! x!}$

Part a

We want this probability:

$P(X \leq 2)= P(X=0)+P(X=1)+P(X=2)$

And we can use the probability mass function and we got:

$P(X=0)=(20C0)(0.2)^0 (1-0.2)^{20-0}=0.0115$

$P(X=1)=(20C1)(0.2)^1 (1-0.2)^{20-1}=0.0576$

$P(X=2)=(20C2)(0.2)^2 (1-0.2)^{20-2}=0.1369$

And adding we got:

$P(X \leq 2)=0.0115+0.0576+0.1369 = 0.2061$

Part b

We want this probability:

$P(X=4)$

And using the probability mass function we got:

$P(X=4)=(20C4)(0.2)^4 (1-0.2)^{20-4}=0.2182$

Part c

We want this probability:

$P(X>3)$

We can use the complement rule and we got:

$P(X>3) = 1-P(X \leq 3) = 1- [P(X=0)+P(X=1)+P(X=2)+P(X=3)]$

$P(X=0)=(20C0)(0.2)^0 (1-0.2)^{20-0}=0.0115$

$P(X=1)=(20C1)(0.2)^1 (1-0.2)^{20-1}=0.0576$

$P(X=2)=(20C2)(0.2)^2 (1-0.2)^{20-2}=0.1369$

$P(X=3)=(20C3)(0.2)^3 (1-0.2)^{20-3}=0.2054$

And replacing we got:

$P(X>3) = 1-[0.0115+0.0576+0.1369+0.2054]= 1-0.4114= 0.5886$

Part d

The expected value is given by:

$E(X) = np$

And replacing we got:

$E(X) = 20*0.2= 4$

3 0

3 years ago

Question 15

Viefleur [7K]

Answer:

0.71

Step-by-step explanation:

1st attempt = $\frac{14}{22} = 63%$ %

2nd attempt = $\frac{22}{28} = 79%$ %

To get the average of something, find the sum of the numbers and then divided the sum by the total number of values there are.

⇒ 63 + 79 = 142

⇒ 142 / 2 = 71%

⇒ 71% = .71

8 0

3 years ago