Answer:
The system that can be used is:


Step-by-step explanation:
We have that:
x is the price of a package of sugar cookies, y is the price of a package of oatmeal cookies.
Shaikha sold 10 packages of sugar cookies and 2 packages of oatmeal cookies for $56.
This means that:

Khalid sold 9 packages of sugar cookies and 3 packages of oatmeal cookies for $60.
This means that 
System that can be used:
The system that can be used is:


I can't understand what you wanted with the second question (or if that is even a question), but the answer to the first one is 42.
Since the number ranges between 3 and 10, an equation can't be made because the number is always unknown or can be different every time
Answer:
68
Step-by-step explanation:
Answer:
10-15
Step-by-step explanation:
Median is the middle of the numbers (or in this case, number sets)
The middle number set is the third.
Thus, the interval would be 10-15.