Even though we are using variables, we still know that "difference" means subtraction. So, if the larger is x1 and x2, those variables go first. The smaller, y1 and y2 will go second. So our problem will look like this:
(x1 < x2 ? x2 : x1) - (y1 < y2 ? y1 : y2)
Answer:
Please refer to the attached graph
Step-by-step explanation:
Knowing the following:
X = amount of money donated to the city youth fund
Y = amount of money donated to the educational growth foundation
We can write the statements in form of equations:
"Will donate up to $500, the money will be divided between two charities"
(a)
"The amount donated to the educational growth foundation to be at least four times the amount donated to the city youth fund"
(b) 
If we graph both equations we can see the area where both conditions are met (see graph attached)
Where the blue line is (a) and the red line is (b)
Shaded area represent all the possible solutions for the donations, for example:
X=100 and Y=400 or
X=50 and Y=200, etc.
30 because it is in the tenths place
18 min per pound
324 min. = X
______ _____
18 1 pound
324 x 1 = 324 324/18= 18 pounds
Cross multiply then divide as above.