Use substitution.
anywhere you see "a" , than you would plug in b + 2 in for it so....
(b - (b + 2)^4
now take the negative sign and distribute it "+"
so b - b is 0, than 0 - (-2) is -2.
so what is (-2)^4 ????? it would become positive 16
well, let's split the hours in minutes, so since 1 hr is 60 minutes, so he can walk 2.833 miles in 60 minutes, well, 3 hrs is 3*60 = 180 minutes, then we add 15 minutes, that's 195 minutes.
if he can walk 2.833 miles in 60 minutes, how long will it be for 195 minutes?

Choice A is false because they are rounding to the nearest tenth (one decimal place) and not nearest hundredth (two decimal places)
Choice B is false as well because 3.825 should round to 3.83. The 5 at the end tells you to round up.
Choice C is false too. The value 3.824 should round to 3.82. Not sure how they got 3.81, so it seems like a deliberate trick question or silly answer.
Choice D is true. The three decimal values are rounded properly to the correct number of decimal places.
Therefore choice D is the answer
Answer:
The problem stats you cannot compress the balls; so you can not round up. You must round down. That means 4 x4 x4. There will be 16 balls per layer and 4 layers. So 48 balls.
The volume of the box is 12%5E3 inches.
You are told the diameter of a ball is 2.5 inches. So the radius of a ball is 1.25 inches
The volume of each ball is %284%2F3%29pi%2Ar%5E3
Subtract the volume of 16 balls from the volume of the box to get the volume of the packing bead material
To get the percentage of beads to box, divide the bead volume by the box volume and multiply by 100%