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# Percents — Basic example

Watch Sal work through a basic Percents problem.

## Want to join the conversation?

• , how did he end up with 20%? I don't understand why its 20%
• 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 ! :)
• 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
• 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.
(1 vote)
• why did he multiplied with 0.7
• 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
• At why does Sal divide 22.40 by 28?
• 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.
• Im having a quiz tomorrow on Ratios, Rates, Proportions, Percents and Units. Which one should i study first?
• Everything because you don't want to fail.
• 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.
• I didn't understand anything 😞
• 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!
• where is 0.7 from?
• To change any decimal to a percent, you just move the decimal 2 places over to the right. With that being said, in this problem, 0.7 (or 70%) is the discounted price. How did we find out? Well the problem told us that the jeans had a 30% discount. That means you take away 30% of the original price. So you could either multiply the number (in this case \$40) by 0.3 (30%) and subtract that from 40 again to get the final price of the discounted jeans, or you can do it as Sal did, which is use the rest of the percent (30% + 70% = 100%) and just multiply by 0.7 (70%) to get the discounted price without subtracting anything.
• how did she get the 70% it doesn't mention it on there ?