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CAHSEE Math 2.3 Mathematical Reasoning 181 Views

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Description:

CAHSEE Math: Mathematical Reasoning Drill 2, Problem 3. Where else on the number line can X be located and still satisfy the above condition?

Language:

English Language

Subjects:

Tags:

Mathematical Reasoning / Analyzing problems

Common Core Standards:

CCSS.Math.Content.6.SP.B.4

Transcript

00:03
Here’s some numbers; shmoop us maybe…
00:09
On a number line, the point X is twice as far from B as it is from A, as shown below.
00:13
Where else on the number line can X be located and still satisfy the above condition?
00:18
Here are the potential answers…
00:25
Okay, we’ve got another logic problem here.

00:27
No advanced mathematics required, so you can put away the graphing calculator.
00:32
Let’s reason through what the problem is actually asking us.
00:35
We have point X, and we can see by looking at the number line that it’s at “3.”
00:40
A is located at “2” here and B is located at “5” here.
00:44
Sure enough, there are twice as many spots between X and B as between X and A.
00:49
Now… we could come up with a formula to figure this thing out… using absolute value…
00:53
…but our time is precious, and we should be able to test each of our answer choices
00:57
quickly and see which one works.
01:01
If X was at -2, there would be 4 spots between
01:04
X and A… 7 spots between X and B. Not quite double.
01:08
If X was at -1, there would be 3 spots between X and A… 6 spots between X and B.
01:14
Boom goes the dynamite. 6 is twice as much as 3…
01:17
…so our answer is B.
01:19
As in, “Bellyache.”
Full Transcript