Answer:
X = 20 and Y = 5
Step-by-step explanation:
you're supposed to substitute the numbers it so the problem x * 2 also means 10 * 2 because x = 10 and y * 1 also means 5 * 1 because y = 5
Choice C is the correct answer because

So in short, 
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The mistake Jerry likely made was that he only cubed the 2 and didn't realize the 6 was part of that cubing process. It seems he didn't add first and decided to cube before adding.
This is probably what steps Jerry did

But as mentioned, those steps are incorrect because the 6 is part of the cubing operation. In other words, Jerry should have added the 6+2 first before cubing afterward (due to PEMDAS determining the order of operations).
Or you could think of it like this

If the perimeter equals 30 and the length is twice the width, then the length is equal to 20 and the width is equal to 10.
Answer:
0.5hrs
Step-by-step explanation:
Let the speed downhill be
,
Speed uphill is
. We are told than speed uphill is
the speed on flat ground. Therefore the speed on level ground will be
.
From this info, we can obtain the actual speed,
on level ground as:

speed, distance and time have the relation
so to obtain time to cover 45miles:

Hence it takes 0.5hrs to cover 45miles on flat ground.