Qr question

[predentgal]

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Two cars start out with one car 104 miles east to the other car. The car that was originally to the east of the other car travels east at a speed of 34mph and the other car travels south at a speed of 25mph. How many miles apart are the cars when they have travelled 4 hours?

A)136
B)236
C)260
D)408

This is how I attempted to solve the problem. Can anyone point out where I went wrong

Lets say car A is the one 104 miles behind B.
34= B-104/4

AND THEN
25= B/4

Then I subtracted B-104 FROM B but i know this is wrong because these 2 equations produce different answers for B

Is there like a standard set up for these reactions?

btw Correct Answer is c)260

 

[Maygyver]

Here's how I would go about this:

First just make a line A--------------------B. That line will be 104 miles
Now, car b will move (34mph)(4hr) east.
Car A will move (25mph)(4hr) to the south.
Notice how this makes a triangle with the legs (25)(4)=100 and (34)(4)+104=236
Use Pythagorean Theorum from that. Does that help?

You could probably do this using the distance formula, but I think it's easier to see and therefore would be a little easier on the DAT to do it this way.

 

[predentgal]

The answer doesnt come out to 260. I dont get it.

 

[qkchen]

the car going east should have traveled 34(4) + 104 = 240 miles (not 236). if you put in 240 miles using Pythagorean Theorem, then you should get 260 on the dot.

 

[UCB05]

nm, qk got it

 

[Maygyver]

the car going east should have traveled 34(4) + 104 = 240 miles (not 236). if you put in 240 miles using Pythagorean Theorem, then you should get 260 on the dot.

Whoops, I added (4)(3) to 4(30).

 

[predentgal]

I get it now.. Thankss a lott.. One more question

Which of the following could be the value of A if the quanitity (5/6 + 3/10 + 5/3 - A) is a positive integer?

a) 1/10
b 1/5
c 2/3
d 4/5
e 6/5

I used an LCD of 30 and added the fractions all together

This gave me 84/30. From my understanding subtracting 84/30 from any of the choices yields a positive number.

If you make choice a have a denominator of 30 then its 3/10.
84/30 - 3/ 10 = a positive number.

The correct answer is D

 

[NewBee12]

One more thing regarding the problem with the cars:
one car traveled 240 miles east and the other 100 miles south. you can avoid using pythagorean theorem if you notice that you have a multiple of a: 5-12-13 triangle

100 = 20 x5
240 = 20 x12
therefore the other side will be: 13 x 20 = 260
hope this helps

 

[Maygyver]

I get it now.. Thankss a lott.. One more question

Which of the following could be the value of A if the quanitity (5/6 + 3/10 + 5/3 - A) is a positive integer?

a) 1/10
b 1/5
c 2/3
d 4/5
e 6/5

I used an LCD of 30 and added the fractions all together

This gave me 84/30. From my understanding subtracting 84/30 from any of the choices yields a positive number.

If you make choice a have a denominator of 30 then its 3/10.
84/30 - 3/ 10 = a positive number.

The correct answer is D

Alright, so you know you have 84/30 - A = 1(or greater, 2 ,3 ,4 etc.)
So if you assume 1 is the lowest you can get, you have:
A=84/30 - 30/30
A= 54/30 = 13/10 This isn't an answer so you can go onto the next.

A=84/30 - 60/30
A=24/30 = 8/10=4/5

The problem with the way you did it, is that 84/30 - 9/30 = 75/30 which is not an integer.

Hope that helps.

 

[predentgal]

oooooohhh I get it now..your the best Maygyver..lol

 

[predentgal]

So macgyver as you could see I'm not that great in math.I'm so scared formath on the real thing! How would you say the QR SECTION was on your Dat.Were there more word problems or just simple math questions?

 

[Maygyver]

So macgyver as you could see I'm not that great in math.I'm so scared formath on the real thing! How would you say the QR SECTION was on your Dat.Were there more word problems or just simple math questions?

Hmm..I would say that there were a fair amount of word problems (maybe a little bit more than Topscore). I think that for the most part the questions were easier than anything you will see in Destroyer. I would suggest going through Destroyer so that you understand how to do all the problems, and then going through a second time. However, during the second run through, I would separate them out into sections of 45 and use them like mini practice exams. I would say doing 40 questions might be more equivalent of the pace you need on the real thing, but if you can train yourself to do 45 Destroyer ones in the allotted time, you will be absolutely golden. Don't get too down on yourself, when I went through Destroyer math there were some questions where I was completely lost. The important thing is being able to understand how to solve that type of a problem and you should be good. As long as you are learning from your mistakes you will be fine on the math. With that said, there were still quite a few non-word problems as well. When is your test date?

 

[predentgal]

June 2nd

 

[Maygyver]

Ah ok, you still have plenty of time to get ready. It's good that you started early. I would suggest getting an SAT book or ACT book. (I'm not sure what is on both of those exams now a days but I would check a book store and see what matches up with the DAT.) I think that should give you a little more background because I think Kaplan was really lacking for QR. After going through that go back through destroyer and see how much of it you can remember how to do. Once you've done a lot of problems it starts to get a little easier. Good luck!

 

[predentgal]

I have destroyer and am almost done with it. I'm definitely gonna go through the problems one more time. Thanks🙂

 

[Maygyver]

No problem. A lot of the Destroyer stuff is tough if you haven't done it in awhile. The real test of how well you will do, is your ability to understand it the second time after you realize how to do it.