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Mathematical Reasoning Videos 30 videos
Mathematical Reasoning Drill 3 Problem 1. Which of the following is the best estimate of [3.05(7.95) - 4]2?
Mathematical Reasoning Drill 3 Problem 2. Which of the following is the best estimate of the final cost of the dress before sales tax?
CAHSEE Math: Mathematical Reasoning Drill 3, Problem 4. Which of the expressions gives the best estimate as to the length of this quadrilateral's p...
CAHSEE Math 2.5 Mathematical Reasoning 201 Views
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Description:
CAHSEE Math Mathematical Reasoning: Drill 2, Problem 5. Which of the following conclusions can be drawn based on the above information?
Transcript
- 00:04
Anyone have a hankering for a slice of piping hot algebra?
- 00:10
Suppose x = 2m and y = 5n, where m and n are positive integers.
- 00:17
Which of the following conclusions can be drawn based on the above information on m and n?
- 00:23
Here are the potential answers...
- 00:28
Okay, this question wants us to use... reason.
Full Transcript
- 00:30
Not the chocolate kind.
- 00:32
What can we deduct from the stuff that's given to us?
- 00:35
Well, let's see. X is equal to 2 times m, which is a positive integer...
- 00:39
...which means that x must be an even number. Because if we're multiplying ANY positive
- 00:43
integer by 2, we're going to wind up with something that's even.
- 00:48
Similar deal with y... except we're multiplying n by 5, so we know y must be a multiple of 5.
- 00:54
Let's look at our answer choices.
- 00:56
X is divisible by 3? Um, no... we know it's divisible by 2, and it MIGHT be divisible
- 01:02
by 3, but we can't be sure.
- 01:04
X is odd? Definitely not. We just decided it had to be even. Next.
- 01:08
Y is a negative number? No way. Not if n is positive and being multiplied by 5.
- 01:14
So it seems like D is going to be the answer to all our prayers, but let's make sure.
- 01:18
Is x times y a multiple of 10?
- 01:21
Well, if one is a multiple of 2 and the other is a multiple of 5...
- 01:25
...then yeah, it makes sense that the two multiplied together would be a multiple of 10.
- 01:29
Our answer is D. As in, "Disney got it wrong."
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