Deductions from the Given Information

The deduction for this problem is rather obvious but very important. $x$ can take any value as long as it's greater than $6$ and less than $7$. This is so important is because it tells us what values we should test. Remember, you don't want to test two values that are bunched together. For example, you wouldn't want to test $6.4$ and $6.5$. Instead, you should test values that are as spread out as possible to figure out what's going on.

Solving the Problem

To solve this problem, I recommend testing the following two values for $x$: $6.1$ and $6.9$. Notice how these two numbers are quite spread out and don't violate the given information. Let's see what happens with our first value:

$$\frac{6.1}{8} = 0.7625$$

Let's test out the second value:

$$\frac{6.9}{8} = 0.8625$$

In the first case, Quantity B is larger than Quantity A. In the second case, Quantity A is larger. Thus, the answer is D, It cannot be determined.