# QR probs help puh leasee

Discussion in 'DAT Discussions' started by salamanda, Jan 6, 2009.

1. ### salamanda 2+ Year Member

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=

#1
Last edited: Apr 22, 2009
2. ### yankees27th 7+ Year Member

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I found the wording for the first question to be kind of confusing. I ended up interpreting it three different ways and got three different answers: \$16, \$25, and \$62.50. If \$60 is the right answer I'll let you know how I did it, otherwise I have no idea haha.
I haven't looked at the second question yet.

Edit: I got C for the 2nd question too. I think it's an error with the question. E would be the answer for if you wanted the amount of interest earned to be double the initial amount put in (aka tripling your money). Or I could be wrong haha. Can someone confirm?

#2
Last edited: Jan 6, 2009
3. ### innocentxgrl 2+ Year Member

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i hope streetwolf helps us with thsi prob... i heard hez a math pro!

4. ### adizzle87 2+ Year Member

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Yeah, CDM does have a good amount of math errors. The other day I actually reported one to the company and per their guarentee I got \$5 back for reporting it. Report those two and explain why, you might get some \$\$ back

5. ### salamanda 2+ Year Member

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#5
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6. ### gentile1225 5+ Year Member

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what is the answer for #1 because i got 50 and i think its just a play on words.

he buys the goods as 80% of the market price and sells them at 20% above the cost price, which is the market price. Therefore he sells that at 1x, buys them for .8x and makes \$10.

1x - .8x = 10
.2x = 10
x = 10/.2
x = 50

does this sound good?

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7. ### gentile1225 5+ Year Member

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sorry, didnt see you already posted the answer. i was in the zone.

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8. ### gentile1225 5+ Year Member

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for the second question, plug in a number so you can see what two times the amount would be. also, if you realize that 12% is approximately 1/8 of the money you are putting in. and nowhere does it say the interest is compounded. so using 64 as the initial amount you put in...

(64/8) * x = 128 << (64/8 is the interest per year, and x is the number of years)
8x = 128
x = 16, but this is in years and remember we said 12% is about 1/8 of 100, but it is actually a little less, so since we rounded up, we round up our answer a little bit too.

16 years *12 months/year = 192 months, or close to 200 months.

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9. ### salamanda 2+ Year Member

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gentile1225,

YOU'RE GOOD. HAHA. when is your DAT?

10. ### FutureInternist 10+ Year Member

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If you want the total prob of 1 apple & 1 mango, you have two routes
i.e. A then M and M then A
So for the first case prob of apple = 5/7, then prob of mango will be 2/6 (6 since you have NO replacement) this gives you (5/7)*(2/6) = 5/21
For the second case prob of mango = 2/7, then prob of apple will be 5/6 giving a prob of (2/7)*(5/6) = 5/21
Now you add these 2 probabilities together (5/21) + (5/21) = 10/21

Hope this is correct

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11. ### Sublimation 5+ Year Member

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uuuggghhh, i did it a weird way so if you dont understand wat im saying dont bother lol. but it only took me seriously on like half a minute actually maybe less to get the answer. Look at it this way its fairly strait forward, cost price is 20% more then market price, so basically he paid the full value for the product. Now since he sold it at 20% more then the cost price and profited 10 dollars. Therefore 20 percent of the market price has to be 10 dollars, his profit. In other words think of the 2 20%s for the cost price and market price diff. and the profit negating eachother. AHHHH its hard to explain how i did it. I kinda played it out in my mind.

Like this

Market Price Cost price Wat he sold it at

>>>Here >>>Here

>>>>Here

Profited 10 dollars. 20% of 50 is 10 dollars. so the market price is 50 dollars. I hope this helps

#11
Last edited: Jan 6, 2009
12. ### salamanda 2+ Year Member

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you all are genius. I am so jealous

13. ### Sublimation 5+ Year Member

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Ait here it is. look i am horrible at explaining things, so if you dont get it, ignore wat i say lol, but if you see what im saying then kudos to u.

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14. ### Sublimation 5+ Year Member

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look ill tell u the same thing i tell my students. These Qs are not designed to take alot of time, just a little bit of intuitive thinking. So if u find urself dwelling too long on one problem skip it, and when u ocme back to it. think to urself, there is a simple and quick way to the solution, and try to use the hints in the problem. if u read it backwards, the Q, it will make perfect sense lol. or so it did to me. I guess cuz im so used to seeing Q like this. The Q pattern never really changes, once u get accustomed to identifying these patterns you will be able to quickly manipulate them. thats y PRACTICE makes perfect . Just practice practice practice practice. practice till ur brain bleeds lool.

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hahahaha
yes i agree

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17. ### Streetwolf Ultra Senior Member Dentist 7+ Year Member

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#3 someone explained.
#2 I read it as 'earns 100 interest' which makes it 100 months.

#1 as follows:

P = purchased
M = market price
C = cost
S = sells

P = 0.8 M
S = 1.2 C
M = 1.2 C

Thus S = M and so P = 0.8 S. In other words he purchases an item for 80% the price he sells it at. This means his profit is 20% of the price he sells it at. If the profit is \$10, and \$10 represents 20% of the selling price, then the item sells for \$50. This last step can be solved quickly in your head or by using ratios. And as we said earlier, the selling price and market price are the same. So the market price is also \$50.

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18. ### gentile1225 5+ Year Member

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sorry salamanda, i didnt ignore your post, i was out all day yesterday. im taking it in a couple of weeks. just hope my qr skills are up to par by then. ive been busting my a** trying to guarantee myself at least a 19. i got a 16 on my first one and i am definitely not looking forward for trial #3. good luck to you studying.

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19. ### salamanda 2+ Year Member

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Sx

#19
Last edited: Apr 22, 2009
20. ### salamanda 2+ Year Member

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Gggg

#20
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21. ### SahimAmd

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Hey I'm studying for the DAT too, just came accross this post and thought I can help with the math questions. Here is what I think.

1)

Same as if you buy a purse at 80% original price sell it back 20% more than you paid for (in another word 100% orginal price) and made \$10. So given \$10 is to 20% what is 100% (which is the original market price that the question asks for). Set up this equation and solve.

\$10 x
---- = --- , x = \$50 (ans: D)
20% 100%

2)

12%
------*m = 200%, m=200 months (ans: E)
12

The key to this problem is using the correct definition for simple interest

3)

The question asks for chances he picks 1 apple and 1 orange but not the order it is in. So calculate the chances for picking up an apple then a mango, and chances for picking up a mango then an apple and add the two probabilities together.

Chance for picking up an apple then a mango is 5/7*2/6=10/42
Chance for picking up a mango then an apple is 2/7*5/6=10/42

Chance for picking 1 apple an 1 mango is 10/42+10/42 = 20/42 or 10/21 (ans: C)