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### Course: Digital SAT Math > Unit 3

Lesson 3: Percentages: foundations# Percents — Basic example

Watch Sal work through a basic Percents problem.

## Want to join the conversation?

- 2:56, how did he end up with 20%? I don't understand why its 20%(15 votes)
- the total was 100 %

but , 22.40/28 = 0.8 or 80%

we paid only 80% of it , so 100 - 80 = 20 %

hope you get it ! :)(32 votes)

- As per Sal's percentage based solution, the answer should be 12.5 bcoz, when he ate 1st bowl, what was left was 92%, and after that he kept consuming 8% every time. so, here 92/8 = 11.5 ( correct ), but now we also have to add the 1st bowl which he ate. which makes (11.5 + 1) = 12.5. This is what I think. If anyone can spot any error in my judgment, please let me know.(21 votes)
- I literally did the same thing, but my guess is, the question says "expect" to eat. so I'm guessing they want an answer excluding the first bowl he already had(9 votes)

- if you have questions like this how do you know if you should answer the question using these steps if there are questions worded or phrased differently(9 votes)
- The best way you can identify a problem like this is if it assumes the starting point is 100%. Like Sal had said, if you are starting from a whole and consistently subtracting the same amount every time, you don't even need to think about the percentages, you can just substitute them as units.(4 votes)

- its easy... In India they teach a very simple method

here the porblem could be solved under 2 mind steps(7 votes)**Can you show the method?? please**(6 votes)

- Im having a quiz tomorrow on Ratios, Rates, Proportions, Percents and Units. Which one should i study first?(0 votes)
- Everything because you don't want to fail.(20 votes)

- why did he multiplied with 0.7(3 votes)
- Hello Sebnem,

The discount was 30% but we still need to pay the other 70%.

Sal does the same thing again when we pay 80% at the counter. Therefore the additional discount was 20%.

Regards,

APD(10 votes)

- At1:15why does Sal divide 22.40 by 28?(4 votes)
- Sal divides 22.40 by 28 to figure out what percent of the already discounted price was paid.

With that information, he could find out what the additional discount was.(6 votes)

- Please, why can't I replay the video after watching?(3 votes)
- I'm not sure. Perhaps you ought to try reloading the page?(1 vote)

- This was extremely simple.

100/8=12.5

12.5 Bowls-1 Bowl= 11.5 Bowls(4 votes) - I didn't understand anything 😞(3 votes)
- After calculating the original discounted price with the 30% off

(28), an easier approach is to find a percent decrease by doing (28 - 22.20 / 28 )100. Hope that helps!(2 votes)

## Video transcript

- [Instructor] We're told today, Ebuka opened a new cereal box. He ate a bowl of the cereal, which was 8% of the
cereal in the entire box. Approximately how many more
bowls of cereal can Ebuka expect to get from this box if he continues to eat
the same amount of cereal in each bowl? All right, pause this video
and see if you can answer this on your own. There are several ways that
you could approach this. You could say, all right, the box starts off with
100% of the cereal. Then in that first bowl, he eats 8%, and so you're left with 92% of the original new box amount of cereal, and then every time, he's going to eat 8%
of the original amount that was in the box. So if now we have 92% of the
original amount in the box, and at every serving, he's
going to eat 8% of it, we just divide by 8% to figure out how many servings he'd have. And so 92 divided by eight. See, eight times 11 is 88, and then you have four more, so this is going to be
11 and a half bowls, and that is this choice right over here. If the percent is confusing, you could say, all right, let's just imagine that
there were, I don't know, 100, pick a unit, in the original box. Then every serving, he eats eight, and so he's left with 92 and then if every serving,
he's eating eight, 92 divided by eight is 11.5.