Amount of money paid by Jeremy as rent and maintenance of shop per month = $1500
Cost of raw materials and manufacturing per month = $6000
Total cost that Jeremy has to spend per month = (1500 + 6000) dollars
= 7500 dollars
Number of individual chocolates sold = 2400
Number of chocolates sold in boxes = 50 boxes
= (12 * 50) chocolates
= 600 chocolates
Then
Total number of chocolates sold by Jeremy = 2400 + 600
= 3000
Now
Price of each chocolate = 7500/3000 dollars
= 75/30 dollars
= 5/2 dollars
= 2.5 dollars
Price of 600 chocolates = 600 * (5/2) dollars
= 300 * 5 dollars
= 1500 dollars
Price of 12 chocolates = (1500/600) * 12
= 15 * 2
= 30 dollars
Then
We can say that each box of chocolate should be sold at $30. All the loose chocolates should be sold at $2.5 each.
we are given

where
y is average gas mileage in miles per gallon
x is speed in miles per hour
we have to find average gas mileage at a speed of 60 miles per hour
so, we have

now, we can plug it and find y

we get

so,
the best approximate for the average gas mileage at a speed of 60 miles per hour is 30.7 mi/gal...........Answer