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### Unit 2: Lesson 4

Lesson 4: Color mixtures

# Understanding equivalent ratios

Sal discusses what it means for two ratios to be equivalent.

## Want to join the conversation?

• At Sal said "the order matters". Why does the order matter?
• Hey Ashi, to respond to your question,the order matters,a lot with ratios. If I had four bananas and fifteen apples and I had to put the amount of apples to bananas, I would have to put 15:4. If I put without being told to put bananas to apples, the problem wouldn't work. I hope this answered your question.
• In the first question, why didn't he multiply both? like, doesn't that mean they ain't equivalent?
• I think what you mean is when he is multiplying one of the stores recipe and not the other one. The thing is, is that when he multiplied the ratio 2:2/1 he multiplied both sides by 2 yes? Which means the value of the ratio hasnt changed but how it is presented is. For example say you were actually making something, and you had the ratio 1:1 (this is mainly because I DONT WANNA DO MATH cough* anyways) and then you multiplied both sides by 4, making 4 servings. the ratio itself is still the same its just presented differently. (this is confusing i know) Basically its like its 1 to 1 yeah? then its 4 to 4. The ratio still means the same its just making more servings. The same goes for the problem Sal is showing, the two when brought to the same amount of servings as the other makes them both equal. If you dont get it might wanna comment and ask for someone else to explain. Keep in mind though that this doesnt apply to all equations. (I cant really explain these examples either because there are none or i just havnt the care to research them. Maybe both). Hope this helps!
• i get the concept, but when I take the tests it says what he's doing is WRONG which does not make sense, does anyone have an explanation?
• There is an explanation for every question on the tests on Khan. Try following those.
• can i add the two values in two ratios and see if they are equivalent?for example in the ration 4:3 , if i add them i would get 7 and in the ratio 20 : 15 , if i add them i would get 35. So can i say that 7 times 5 is 35 , so in each value of the ratio 4:3 , i need to multiply with 5 to get 20 : 15?
• You're making it more complicated than it needs to be.
Why don't you just look at 4 and 20. 4*5 = 20. Then, look at 3 and 15. if 3*5=15 (which it does), then you have an equivalent ratio.

Or, think of ratios as fractions (which they are). Fully reduce 20/15 by removing a common factor of 5 and you get 4/3. So, the ratios are equivalent.

For more complicated ratios, you can use cross multiplication.
If 4/3 = 20/15, then 4(15) must equal 3(20).

Hope this helps.
• I AM KINDA CONFUSED BC WHEN I DO THE WORD PROBLEMS FOR EXAMPLE: Victoria's favorite cookie recipe uses 170 grams of butter for every 250 grams of flour. Victoria's daughter made cookies using 340 grams of butter for every 400 grams of flour.
What will Victoria think of her daughter's cookies? IT DOESNT MAKE ANY SENCE FOR ME BC I DONT KNOW IF I AM SUPPOSED TO MULTIPLY OR DIVIDE AND I DIDNT UNDERSTAND THE VIDEO...
• is 340 divisible by 170 if so by how much then do the same with the other ration 250 divide 400 by 250 then see if you get the same quotient if you dont then its not equivalent if you want to knwo which is higher and which is lower in a certain substance or which substance is lower or higher then multiply the first ratio by the quotient that was revealed when youdivided it by the second ratio's first number with and if the resulting ratio is lower or higher you can answer it in the question
• how do you get 9:5 please tell me
• you take and divide both of them by 2.
• to is understood, but is the question not state :
"Which dipping sauce has stronger mustard flavour?"

Firstly: It's written stronger MUSTARD flavour, and we can clearly see that Burgur Barn uses 1/2 or 0.5 or one-half spoonful mustard, and Sandwhich Town uses 1 spoonful of mustard. So isn't it clear that Sandwhich Town has a stronger mustard flavour?

Secondly: Even if we look at it as a whole or one dipping sauce, we would find that Sandwhich Town has stronger mustard flavour.

I understand that the answer was same because we are doing equivalent ratios so the answer is "same", but is this answer not wrong for this question? Or is my understanding wrong?
• actually is it my eyes being dumb or does burger barn have half the serving as sandwich town