He saves $200 (the amount of change over the original amount $500
200/500 = 2/5 and 2/5 = 40% (divide 2 by 5 and get .4 which = 40%)
40% discount is the answer to your question
Answer:
see explanation
Step-by-step explanation:
I don't have graphing facilities but can give you the vertex and 1 other point.
Given a parabola in standard form
y = ax² + bx + c ( a ≠ 0 )
Then the x- coordinate of the vertex is
x = - 
y = - x² - 2x + 8 ← is in standard form
with a = - 1 and b = - 2 , then
x = -
= - 1
Substitute x = - 1 into the equation for corresponding value of y
y = - (- 1)² - 2(- 1) + 8 = - 1 + 2 + 8 = 9
vertex = (- 1, 9 )
To obtain another point substitute any value for x into the equation
x = 0 : y = 0 - 0 + 8 , then (0, 8 ) is a point on the graph
x = 2 : y = - (2)² - 2(2) + 8 = - 4 - 4 + 8 = 0 then (2, 0 ) is a point on the graph
Answer:
The probability that the student answers at least seventeen questions correctly is
.
Step-by-step explanation:
Let the random variable <em>X</em> represent the number of correctly answered questions.
It is provided all the questions have five options with only one correct option.
Then the probability of selecting the correct option is,

There are <em>n</em> = 20 question in the exam.
It is also provided that a student taking the examination answers each of the questions with an independent random guess.
Then the random variable can be modeled by the Binomial distribution with parameters <em>n</em> = 20 and <em>p</em> = 0.20.
The probability mass function of <em>X</em> is:

Compute the probability that the student answers at least seventeen questions correctly as follows:


Thus, the probability that the student answers at least seventeen questions correctly is
.
The formula for that area would be A=1/2xbxh so you would do A=1/2x3.5x3 and that equals 5.25