Hello!

To find the percent tax, use the equation:

Substitute in the given values:

Multiply by 100 to find the percent tax:

Answer:
x = -5
Step-by-step explanation:
-5(1 - 5x) +5(-8x - 2) = -4x – 8x
First lets simplify each side of the equation.
-5+25x-40x-10 = -4x-8x
Combine like terms
-15x-15=-12x
Add 15x to both sides (addition property of equality)
-15=3x
Divide each side by 3 (division property of equality)
x=-5
The answer is x = -5
Answer:
-10
Step-by-step explanation:
Just set up a simple equation.
Answer:
a) p=0.2
b) probability of passing is 0.01696
.
c) The expected value of correct questions is 1.2
Step-by-step explanation:
a) Since each question has 5 options, all of them equally likely, and only one correct answer, then the probability of having a correct answer is 1/5 = 0.2.
b) Let X be the number of correct answers. We will model this situation by considering X as a binomial random variable with a success probability of p=0.2 and having n=6 samples. We have the following for k=0,1,2,3,4,5,6
.
Recall that
In this case, the student passes if X is at least four correct questions, then

c)The expected value of a binomial random variable with parameters n and p is
. IN our case, n=6 and p =0.2. Then the expected value of correct answers is 