Percent word problem example 2 | Decimals | Pre-Algebra | Khan Academy

It's nice to practice conversion problems, but how about applying our new knowledge of percentages to a real life problem like recycling? Hint: don't forget your long division!

Missed the previous lesson?

Pre-Algebra on Khan Academy: No way, this isn't your run of the mill arithmetic. This is Pre-algebra. You're about to play with the professionals. Think of pre-algebra as a runway. You're the airplane and algebra is your sunny vacation destination. Without the runway you're not going anywhere. Seriously, the foundation for all higher mathematics is laid with many of the concepts that we will introduce to you here: negative numbers, absolute value, factors, multiples, decimals, and fractions to name a few. So buckle up and move your seat into the upright position. We're about to take off!

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[LynnToledo]

I like how you explain stuff. You're an awesome teacher I never have hated algebra if you were my professor.

[TheFrostLeader]

IDK why but my classmates are obsessed with Khan Academy (the website). Very awesome dude!

[griffyspacemun]

I missed a week of class and my teacher told me about you and now I understand thanks!

[bunbun]

Why does no one talk about his voice? Its amazing, it makes me able to get thru a monday with little to no sleep

[zayan]

nice video you are a great explainer in all various subjects including maths

[VickiBee]

My friend showed me an easy way to do it when the bottom number can be evenly divided into 100.

13/20 = x/100. In order to get the number for x he multiplied by 5. 20 x 5 = 100 and 13 x 5 = 65. 65/100 = 65%.

But you can't do it with numbers that don't go into 100 evenly, like 18.
Then you have to do it the other way.

[jessicav]

Awesome video! I am looking to purchase a book to help me practice word problems, I struggle a lot with them and I am getting ready to prepare for the TEAS 6 exam. Do you have any recommendations for a book?

[DellorWeekly]

you can do 100 divided by 18 which will give you the "even" multiplier into 100, then multiply the other amount by the amount from this result. it's just more work this way.

[RumorWeeds]

The second option wouldn't always work because what if it was (e.g.) 13/21? 21 can't go into 100 like he did there.

[brittanychipette]

Why do people think that everyone is on their level? My God man not everyone can ace this stuff like you can, so if you already know it why are you watching this?! -_- It may be soooo easy for you, but completely difficult for others. Everyone learns differently. People need to realize that.

[anthonybustamante]

I did this the easier way I did =
13 / 20

20 x 5 = 100
13 x 5 = 65
(65/100) easier

[honcho]

same paint brush i have an A because on this awsome guy XDXDXDXD

[RyantheCanuckpirate]

Everyone's at a different level of math. There's probably a chunk of people in the world who would say the same thing about the videos you find useful.

[calvinlimify]

Why are you doing such a simple qns? Omg