Suppose the dimensions of the rectangle is x by y and let the side enclosed by a house be one of the sides measuring x, then the sides that is to be enclosed are two sides measuring y and one side measuring x.
Thus, the length of fencing needed is given by
P = x + 2y
The area of the rectangle is given by xy,
i.e.

Substituting for y into the equation for the length of fencing needed, we have

For the amount of fencing to be minimum, then

Now, recall that

Thus, the length of fencing needed is given by
P = x + 2y = 24 + 2(12) = 24 + 24 = 48.
Therefore, 48 feets of fencing is needed to enclose the garden.
Here it goes:
a. Because you have four blue marbles out of the 12 total marbles, the probability is 4/12. YOU MUST SIMPLIFY down to 1/3.
b. There are 12 marbles in the bag right now, and the probability is 4/12, you must add some marbles. 1/10 multiplied by 4 is 4/40. There are 4 blue marbles right now, and 40 minus the 12 there are right now is 38, so you would need to add 38 non-blue marbles.
There are 2 half-miles in a mile. Thus, doubling 8.5 minutes will give you the answer.

minutes per mile or .17 miles per minute.