Answer:
Step-by-step explanation:
Given data:

standard deviation is 
As distribution is normal in shape and values are symmetrical
The standard deviation rule says that 95% of observation lies between the second standard deviation of the mean
so, approximately only 5% of observation lies outside the interval and normal shape is symmetric. hence approximately 0.15% of observation lies above the interval


almost 0.15% of students spent more amount is 529
Answer:
A.
Step-by-step explanation:
12.5/10=1.25.
12.5/8=1.56
12.5/12=1.04
12.5/6=2.08
it's important to know what 1/2 is, 1/3 is, 1/4 is and 1/5 it's also important to know things like 2/2, 2/3, 3/3, 2/4, 3/4, 4/4, 2/5, 3/5, 4/5, and 5/5. You don't need this until 8th grade though. But get on it if you can. Ask your parents or teacher.
The two equations are

and

the first equation can be solved for x to be

next you can substitute x in the second equation

Distribute 4 to everything in the parentheses

combine like terms:

subtract 28 from both sides of the equation

divide both sides by -1.5

plug this in to the original equation of x+y=7

subtract 4 from both sides.

Final Answer: they bought 3 adult tickets and 4 student tickets
Hope this helps!
Answer:
Step-by-step explanation:
You have 3 points and need to find ax2 + bx + c = y. First use (0,2). x is zero, so y = 2 = c. You have c. Now put (-1,0) into the equation. 0 = 1a -b + 2. Rearrange so you get b = a + 2. Now use the other point. a*(-2 squared) + b*(-2) + 2 = 0. Simplify and substitute (a + 2) for b and you will have the answer.