So we are given that the mean is 42% and the sd (standard deviation) is 8%
Assuming our data is normal we can use the 68-95-99 rule
So one thing you should realize is that 42% + 8% is 50% which is passing. That is one standard deviation higher. So we use:
100 - 68 - 13.5 - 2.35 - 0.15 = 16. That means 16% of students passed the test. Which is terrible. They probably need to hit the books more.
Anyways if you have any question feel free to message me!
Hopes this helps!
Answer:
x = 9 ± √14
Step-by-step explanation:
x² − 18x + 67 = 0
Move the constant to the other side:
x² − 18x = -67
Take half of -18, square it, and add to both sides.
(-18/2)² = (-9)² = 81
x² − 18x + 81 = -67 + 81
x² − 18x + 81 = 14
Factor the perfect square:
(x − 9)² = 14
Solve for x:
x − 9 = ±√14
x = 9 ± √14
The answer is C) all real numbers greater than or equal to one.
Hope this helps!
Im pretty sure it would be doubling the length of each side
