Answer:
The correct answer is B) d=250t.
Step-by-step explanation:
B is the correct answer because the total distance (d) equals 250 multiplied by the minutes (t) the runner has ran.

the first step is to deal with the negative exponents, which causes numbers to go to the other side of the fraction
8x^{-9}+(-3x^{-3}y^{-2})(\frac{5}{x^6y^{-2}})
goes to

now we can simplify the multiplied terms

Now that we have common bases, we can add the 2 fractions together to get

In order to find the smallest amount of cardboard needed, you need to find the total surface area of the rectangular prism.
Therefore, you need to understand how the cans are positioned in order to find the dimensions of the boxes: two layers of cans mean that the height is
h = 2 · 5 = 10 in
The other two dimensions depend on how many rows of how many cans you decide to place, the possibilities are 1×12, 2×6, 3×4, 4×3, 6×2, 12×1.
The smallest box possible will be the one in which the cans are placed 3×4 (or 4×3), therefore the dimensions will be:
a = 3 · 3 = 9in
b = 3 <span>· 4 = 12in
Now, you can calculate the total surface area:
A = 2</span>·(a·b + a·h + b·h)
= 2·(9·12 + 9·10 + 12·10)
= 2·(108 + 90 + 120)
= 2·318
= 636in²
Hence, the smallest amount of carboard needed for the boxes is 636 square inches.