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Ratios, Percentages, and Proportions Videos 55 videos
SAT Math 10.3 Geometry and Measurement. What is the ratio of birds to dogs?
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SAT Math 2.2 Statistics and Probability. What percent of her recommended daily intake of 2000 calories did she consume?
CAHSEE Math 3.2 Mathematical Reasoning 184 Views
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Description:
Mathematical Reasoning Drill 3 Problem 2. Which of the following is the best estimate of the final cost of the dress before sales tax?
Transcript
- 00:03
Here’s your shmoop du jour…
- 00:05
Brook’s sister dreams of finding a cure for cancer.
- 00:08
Brook… has slightly lower aspirations. She dreams of finding the best bargain.
- 00:13
Brook purchased a dress that originally sold for $49.95 on sale at 15% off.
- 00:18
On top of these savings, she used her store charge card and
Full Transcript
- 00:21
received an additional 3% off on top of the 15%.
- 00:25
Which of the following is the best estimate of the final cost of the dress before sales tax?
- 00:30
And here are the potential answers...
- 00:35
OK, so this question is testing us on our ability to round and estimate…
- 00:40
…and work quickly through a problem with relatively complex percentage applications.
- 00:45
The answer set has no pennies in it so it’s obvious that “close” is good enough for this problem.
- 00:50
So anyway… Brook picked up her fifty dollar dress –
- 00:53
and yeah we can round the 49.95 to 50… at 15% off.
- 00:59
That is, we take 15 percent of 50 which is 7 dollars and 50 cents and subtract it from the fifty.
- 01:06
That gets us 42 dollars and 50 cents after the sale discount.
- 01:11
Brook also got 3 percent off of the 50 dollars…
- 01:13
…read the wording of the question carefully – it’s not off of the 42.50…
- 01:18
…and that 3% off of the 50 is a $1.50.
- 01:21
Ok, subtract the $1.50 now from the 42.50 and we have 41 bucks…
- 01:26
…the answer is B.
- 01:27
As in… “Bargain… achieved.”
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