Answer:
The minimum boxes of cookies is 39
Step-by-step explanation:
Let
x ----> the number of boxes of cookies sold
y ----> the number of boxes of candies sold
we know that
The word "at least" means "greater than or equal to"
so
The inequality that represent this problem is

The solution is the shaded area above the solid line 
using a graphing tool
The solution is the shaded area -----> see the attached figure
Find out the minimum boxes of cookies needed to sell to reach the goal
assuming only cookies are sold
For y=0


solve for x

Round up
therefore
The minimum boxes of cookies is 39
Answer:
Error Bound = 0.04
Step-by-step explanation:
Whenever we want to estimate parameter from a subset (or sample) of the population, we need to considerate that your estimation won't be a 100% precise, in other words, the process will have a random component that prevents us from always making the exact decision.
With that in mind, the objective of a confidence interval is to give us a better insight of where we expect to find the "true" value of the parameter with a certain degree of certainty.
The estivamative of the true difference between proportions was -0.19 and the confidence interval was [-0.23 ; -0.15].
The question also defines the error bound, as the right endpoint of the confidence interval minus the sample mean difference, so it's pretty straight foward:
Error Bound = 
The interpretation of this would be that we expect that the estimative for the difference of proportions would deviate from the "true" difference about
or 4%.
So first write out the expression:

take two 10's from the top to cancel with the two 10's on the bottom.
3.9/1.3 is 3.
The answer is 3*10^3