Answer:
a) 
With:


b) 

c) 

d) 


Step-by-step explanation:
For this case we know the following propoertis for the random variable X

We select a sample size of n = 81
Part a
Since the sample size is large enough we can use the central limit distribution and the distribution for the sampel mean on this case would be:

With:


Part b
We want this probability:

We can use the z score formula given by:

And if we find the z score for 89 we got:


Part c

We can use the z score formula given by:

And if we find the z score for 75.65 we got:


Part d
We want this probability:

We find the z scores:



Let’s find 1% of the markup first.
20 x 0.01 = $0.20
$0.20 x 8 = $1.60 markup.
$20 + $1.60 = $21.60 total.
Adrianna made $21.60 total, including markup.
Hope that helped! :)
Answer:
x=-8 and y=9
Step-by-step explanation:
rewrite the equations to x+2y=10,3x+4y=12
sub 2y from both sides x+2y-2y=10-2y
substitue x=10-2y in 3x +4y=12
3(-2y+10)+4y=12
distribute
add-30 to both sides
divide both sides by -2
y=9
sustitute 9 for y in -2y+10=x
x=-8
(10² ÷ 5) × (3 + 7) = 200
Answer:
7^8
Step-by-step explanation:
when multiplying exponents with the same base, you add the exponents together to get your answer. you can even check it with a calculator.