Answer:
(2x + 3)(x - 7)
Step-by-step explanation:
Answer:
Step-by-step explanation:
Let's call lifeguarding L and car washing W. In order to write a system, we need to first separate the NUMBER of hours worked from the MONEY earned, because they are very different things.
If she works 10 hours, that is the number of hours worked between both jobs. Therefore, the equation for the NUMBER of hours worked is
L + W = 10.
If she earns $13 an hour lifeguarding, the expression for that is 13L; if she earns $12 an hour car washing, the expression for that is 12W. The MONEY she earned together by doing both those jobs is
13L + 12W = 124
There you go!
15% of $2.15 is 0.3225
And 2.15-0.3225 is $1.83
So the discount is 0.3225
And the selling price is $1.83
The expectation, E(3y +2) and variance, Var(3y+2) of the random variable are 13.4 and 19.44 respectively
<h3>How to determine the expectation and variance of a random variable?</h3>
The expectations or expected value E(y) of a random variable can be thought of as the “average” value of the random variable. It is also called its mean
By definition:
if y = ax + b
then E(y) = aE(x) + b
where a,b = constant
The variance V(y) of a random variable is the measure of spread for the distribution of a random variable that determines the degree to which the values of a random variable differ from the expected value
By definition
if y = ax + b
V(b) = 0
V(y) = V(ax) + V(b)
= a²V(x) + 0
where a,b = constant
Given: E(y)= 3.8 and Var(y)= 2.16
Calculate E( 3y +2) and Var( 3y+ 2)
E(3y +2) = 3E(y) + 2 since E(y) = 3.8
= 3×3.8 + 2
= 11.4+2
= 13.4
Var(3y+2) = 3²Var(y) + 0
= 9×2.16
= 19.44
Therefore, E(3y +2) is 13.4 and Var(3y+2) is 19.44
Learn more about expectations and variance on:
brainly.com/question/15858152
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