You would have no problem at all if it said "7 cows minus 2 cows", or "7 books minus 2 books". The THINGS just happen to be m's instead of cows or books.
When looking at a rectangular prism, we know that Volume = length * width * height
If we are given that the volume of the prism is 280 cubic meters (m^3), the length is 8 meters, and the width is 7 meters, we can fill in our equation.
280 = 8 * 7 * height
280 = 56 * height
Because we are solving for the height, we divide both sides by 56
280/56 = height
height = 5 meters
Here's the way I see it: 5 cards are drawn, one by one, without replacement. Half (or 26) of the original deck are black and half (26) are white.
P(5 are not black) = P(5 are red)
P(5 are not black) = P(first card is red) * P(second card is red) * P(third card is red)*P(fourth card is red)*P(fifth card is red) =
(26/52) * (25/51) * (24/50) * (23/49) * (22/48) = 0.025 (answer)
We start with 52 cards. We draw one, leaving 51 cards, 25 of which are red. And so on.
The values of x and y are 0.2 and 0.4 respectively.
<em><u>Explanation</u></em>
The given proportions are.....
and 
From the second proportion, we will get....

Now, we will plug this
into the first proportion. So we will get....

So, the values of x and y are 0.2 and 0.4 respectively.