Well this is pretty simple. So the first thought is that the peanut butter would be 10$ and the jam would be 0.20$, however, the peanut butter would not be 10$ more. Instead, subtract the 10$ from the total, which gives you 0.20$, and then divide that by two. Now you have 0.10$ for each, along with another 10$ for the peanut butter. The peanut butter would be $10.10, and the jam would be 0.10$ (that's pretty cheap!).
Solve the first equation for y.
3x+y=2
y=2-3x
Substitute
4x+(2-3x)=20
4x+2-3x=20
x=18
So, questions 1 through 3 are pretty vague and you can basically put whatever you think. But... as a hint you might want to base your answers to 1 through 3 on question 4, which is more specific and gives you some clues.
For example, question 2 asks "When do people usually need Kleenexes?" Question 4 basically answers this for you by saying "...blah blah blah are used throughout the duration of a cold." So you could easily say that people usually need Kleenexes when they are sick. You could use this same type of reasoning to answer questions 1 and 3.
To answer 4 itself you need to know how to use confidence intervals. Are you familiar with that?
Question 5 will be based off of your answer to question 4.
(2x-4)(x+5)
2x^2+10x-4x-20
2x^2+6x-20
which would be answer A for you
hopes that help all you need to do is foil
