Answer:
85%
Step-by-step explanation:
If she got 3 wrong then it means she got 20-3 right, so she got 17 questions right.
From there we get the fraction: 17/20
To make the a percentage we times both the top and bottom by 5 (because 20 x 5 = 100)
By doing that we get 17x5/20x5
= 85/100
That is equal to 85%
Answer:

Step-by-step explanation:
we have

Adds the terms
Group terms that contain the same variable

Combine like terms

where

therefore

We will see that the probability of x taking on a value between 75 to 90 is P = 0.5
<h3>
How to get the probability?</h3>
We know that x is a continuous random variable uniformly distributed between 65 and 85.
This means that the probability that x value y in the range is such that:
1 = P(y)*(85 - 65) = P(y)*20
1/20 = P(y).
Now, the probability of x taking a value between 75 and 85 is:
P(75 to 85) = (1/20)*(85 - 75) = 10/20 = 0.5
And the probability between 85 and 90 is zero (because the maximum value that x can take is 85, so this part does not affect).
Then we conclude that the probability of x taking a value between 75 to 90 is:
P(75 to 90) = P(75 to 85) + P(85 to 90) = 0.5 + 0 = 0.5
If you want to learn more about probability, you can read:
brainly.com/question/251701
Answer:
5+7x
Step-by-step explanation:
1/2(6-4x) +2 +9x
3-2x+2+9x
5+7x
The total amount that Shelley earned is $423.88.