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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?
SAT Math 2.3 Numbers and Operations. If Joaquin invests $500, how much will the investment be worth after 3 years?
Percents and Proportions 4514 Views
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Description:
Looking to con someone out of 40% of a pizza? You've come to the right place. Just don't try that on us.
Transcript
- 00:04
Percent and Proportions, a la Shmoop. Candace never got the popular boy.
- 00:10
Back in high school she had acne, headgear... and it was the 80's.
- 00:15
But now that she's on the show Life-Threatening Makeover...
- 00:18
...she's gotten a chemical peel, tooth veneers, Lasik eye surgery, liposuction and
- 00:24
hair extensions. Right now, she's about to get out of her
Full Transcript
- 00:27
car and approach the boy she dreamed about all through high school..
- 00:30
...but she's parked under a tree... If two hundred pigeons sit in that tree and
- 00:35
25 percent of them poop on Candace, how many pigeons poop on Candace?
- 00:41
Percent means "per hundred".
- 00:43
We can write an equation that states:
- 00:46
Some part of the pigeons... over the whole number of pigeons... equals some percent
- 00:51
of 100.
- 00:54
Let's replace these words with variables.
- 00:58
A over B equals P over 100. Which numbers can we plug in?
- 01:04
B is our total number of pigeons, which we know is 200.
- 01:11
And P is our percent, which we know is 25.
- 01:14
Now the equation only has one variable, so let's solve for A.
- 01:21
Multiply both sides by 200, and we get A equals 25 times 2...
- 01:28
...which simplifies to 50. So 50 pigeons poop on Candace just as she
- 01:34
exits the car. Candace just can't catch a break.
- 01:37
Oh well, at least Blake didn't see.
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