Assuming the sheet is a square
see diagram
the length will be 20-2x
the width will be 20-2x
and the height will be x
the volume will be (20-2x)(20-2x)(x)
You haven't provided any value, but I can tell you the solution set for the inequality.
First of all, expand both sides:

Add 3x to both sides:

Add 6 to both sides:

Which is of course equivalent to

Divide both sides by 9

So, every number smaller than 2 is part of the solution of this inequality.
Answer:
70
Step-by-step explanation:
First, set up the ratio of c:t, which is 12:8. Then set up your new ratio of c:t, which is 105:?. The way I find the easiest is to divide 105 by 12, which is 8.75, then multiply that by 8, which is 70. To check if it's right, just divide 12 by 8, and 105 by 70, and if they're the same number, you've got it right.
Ps. I'm guessing you meant to ask the minimum number of trucks, not cars.
17 bc I did it trust me pls