A.would be 50 cents and im not entirely sure about b but i think its 8
Let x be the number of racing bikes, and let y be the number of mountain bikes.
1) 140x + 110y = 26150
2) 180x + 120y = 31800
Solve for one of the variables and plug that in to the other equation:
From equation 1: 140x = 26150 - 110y
x = (26150-110y)/140
Plug this into equation 2:
180((26150-110y)/140) = 31800
Solve for y, and find that y = 85 (the number of mountain bikes).
Plug that y into either equation to find x:
140x + 110(85) = 26150
x = 120 (the number of racing bikes).
So the answer is: 120 racing bikes and 85 mountain bikes.
Answer:



Step-by-step explanation:
Given




Required
The dimension that minimizes the cost
The volume is:

This gives:

Substitute 


Make H the subject


The surface area is:
Area = Area of Bottom + Area of Sides
So, we have:

The cost is:



Substitute:
and 



To minimize the cost, we differentiate

Then set to 0


Rewrite as:

Divide both sides by W

Rewrite as:

Solve for 


Take cube roots

Recall that:







Hence, the dimension that minimizes the cost is:



This is only my opinion. I could be wrong.
My guess is:
Somebody else used that book before you, maybe last year or
the year before, and it was somebody who didn't mind writing
in his book.
One day he didn't have time to write down the homework in his
assignment notebook, so he just circled the homework problems
in his textbook.