MATH Destroyer vs. DAT BC QR (specific question type)

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Math Destroyer and DAT BC have similar QR question, but the answers that they have for this specific type of question always differs. Someone please tell me the correct approach, thank you! Ex: 30% pop. loves cheese, 70% (or like 50%) pop. loves yogurt, 11% loves cheese and yogurt, what percentage like cheese or yogurt, but not both? (I feel like I worded this wrong, but if you've taken the test, you know what I'm talking about, thanks!!!)
 
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The way I approached this type of question was to always imagine a population of 100 people. So in this case 30 people love cheese (this seems like a low number everyone loves cheese lol), 70 love yogurt, and 11 love cheese and yogurt. Now of the 30 that love cheese, 11 of them also like yogurt, so 30-11=19 only love cheese. For the 70 that love yogurt, 11 also love cheese, so 70-11= 59 only love yogurt. (19 + 59) / 100= those that love either only cheese or only yogurt but not both!
 
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tarheel2017 said:
The way I approached this type of question was to always imagine a population of 100 people. So in this case 30 people love cheese (this seems like a low number everyone loves cheese lol), 70 love yogurt, and 11 love cheese and yogurt. Now of the 30 that love cheese, 11 of them also like yogurt, so 30-11=19 only love cheese. For the 70 that love yogurt, 11 also love cheese, so 70-11= 59 only love yogurt. (19 + 59) / 100= those that love either only cheese or only yogurt but not both!
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Okay, that's how I've been doing it, but one problem in the Math Destroyer does it differently. They do 30+70-11 instead of what would be 21, if that makes sense, and I'm not sure why they do this. I get it right on bootcamp and wrong in Math Destroyer. It's so frustrating, bc I have my test in a week 🙁
 
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Yeah for a lot of QR, just use 1/10/100 as baselines. Same for percent increase problems (apples increased 20% in price then decreased 27%, what is the overall percent decrease?). Just practice more and you'll get it!


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spressomfs said:
Yeah for a lot of QR, just use 1/10/100 as baselines. Same for percent increase problems (apples increased 20% in price then decreased 27%, what is the overall percent decrease?). Just practice more and you'll get it!


Sent from my iPhone using SDN mobile
Click to expand...

I think you misunderstood my question. I'm fine with % differences, I'm having an issue with disagreeing answers from Bootcamp and Math Destroyer on questions where they say "x% like A and y% like B, Z% likes A and B, what percentage likes either blah or blah but not both?"
 
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Oh, yeah I noticed this too! I think the wording of the question might be slightly different which enables Destroyer to be (A+B)-C to be the answer, but in Bootcamp the (A+B)-2C to be the answer.. Not sure, I just go with the latter.
 
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spressomfs said:
Yeah for a lot of QR, just use 1/10/100 as baselines. Same for percent increase problems (apples increased 20% in price then decreased 27%, what is the overall percent decrease?). Just practice more and you'll get it!


Sent from my iPhone using SDN mobile
Click to expand...


FYI for percent increase/decrease problems it's a bit quicker to do (20% increase) x1.2 (27% decrease) x0.77 ect. Then you don't have to work it out in theend. I find that speed is your friend in QR.
 
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spdental said:
FYI for percent increase/decrease problems it's a bit quicker to do (20% increase) x1.2 (27% decrease) x0.77 ect. Then you don't have to work it out in theend. I find that speed is your friend in QR.
Click to expand...
I'll give this a go! Usually its easy to eyeball a 25% increase being $1-->$1.25, then I'll usually just multiply by (1-x%) to get it. Your way seems faster though.
 
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spressomfs said:
Oh, yeah I noticed this too! I think the wording of the question might be slightly different which enables Destroyer to be (A+B)-C to be the answer, but in Bootcamp the (A+B)-2C to be the answer.. Not sure, I just go with the latter.
Click to expand...

Dang, I really tried to find the difference in the wording too and it's pretty exact. Sucks.
 
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For QR I thought the test was much closer to Bootcamp than it was to Destroyer. I would probably recommend attacking a problem like that in the way you did it for bootcamp.
 
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I think it has to do with whether or not they include "but not both."
Ex #1: "If 30% like cheese, 50% like yogurt, 11% like both cheese and yogurt. What is the % that like cheese or yogurt, but not both?" (30-11)+(50-11)=58
Ex #2: "If 30% like cheese, 50% like yogurt, 11% like both cheese and yogurt. What is the % that like cheese or yogurt?" 30-11=19... 50-11=39... 19+39+11=69.
For example #2, they are just asking for how many likes either cheese or yogurt, not to exclude those who like both, but you still need to subtract the 11 once bc you don't want to count for the same 11 twice! Those 11 still like cheese or yogurt!!! lol.
*This is just how I have always thought of it! So if y'all see this as flawed let me know! 🙂
 
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Clight96 said:
Math Destroyer and DAT BC have similar QR question, but the answers that they have for this specific type of question always differs. Someone please tell me the correct approach, thank you! Ex: 30% pop. loves cheese, 70% (or like 50%) pop. loves yogurt, 11% loves cheese and yogurt, what percentage like cheese or yogurt, but not both? (I feel like I worded this wrong, but if you've taken the test, you know what I'm talking about, thanks!!!)
Click to expand...
There's a difference when the question asks for: what percentage of the population like A or B and when the question asks what percentage of the population likes A or B BUT NOT BOTH.
You can always use a Venn diagram if you wish.

Hope this helps.
 
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Anyone get to figure this out? Using the approach from Destroyer or BC leads to a different answer for basically the same question
 
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