Remainders

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Remainders

by Brent@GMATPrepNow » Wed Dec 17, 2008 5:03 pm
When the positive integer x is divided by 11, the quotient is y and the remainder is 4. When 2x is divided by 8, the quotient is 3y and the remainder is 2. What is the value of 13y - x ?
A) -4
B) -2
C) 0
D) 2
E) 4

Answer: D

I'd rank this one in the 650 range. It's reasonably complex, and it has the potential to be a time drain if you're not careful. See if you can solve it within 2 minutes.
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by cramya » Wed Dec 17, 2008 5:08 pm
x=11y+4
2x = 24y+2

Solve y=3
x=37

3y-x = 39-37

=2


D)

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by cramya » Wed Dec 17, 2008 5:16 pm
Brent,

Beef it up to 700's please. Even if I cant solve I will definitely have some takeaways... I am sure my buddy Logitech will :-)

Thanks for this one by the way! How about 3-5 questions(ps- ds put together) a day, Brent???

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by dmateer25 » Wed Dec 17, 2008 5:18 pm
cramya wrote:x=11y+4
2x = 24y+2

Solve y=3
x=37

3y-x = 39-37

=2


D)
I can't even get to the question before you respond! :shock: haha good work cramya.

I worked the problem the exact same way. Took just under 2 mins for me.

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by cramya » Wed Dec 17, 2008 5:19 pm
Dmateer,
U r good! I have seen some excellent posts from u on this forum. Good luck wiht ur preps!


See a around...

Regards,
CR

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by Brent@GMATPrepNow » Wed Dec 17, 2008 5:33 pm
Brent,

Beef it up to 700's please. Even if I cant solve I will definitely have some takeaways... I am sure my buddy Logitech will

Thanks for this one by the way! How about 3-5 questions(ps- ds put together) a day, Brent???
That's a pretty tall order. These questions take quite a while to create. I'm probably good for 1 or 2 a day tops.

I'll see what I can do
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by Brent@GMATPrepNow » Wed Dec 17, 2008 5:41 pm
x=11y+4
2x = 24y+2

Solve y=3
x=37

3y-x = 39-37
=2
D)
There's actually a shortcut here that will save a lot of time.

Once we get to:
x=11y+4
2x = 24y+2

We can rewrite as:
(1) x - 11y = 4
(2) 2x - 24y = 2

We don't need to solve for x and y at this point.
The goal is to find the value of 13y - x

If we subtract (1) - (2), we get 13y - x = 2 --> D
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by cramya » Wed Dec 17, 2008 5:46 pm
Thanks!

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by logitech » Wed Dec 17, 2008 5:49 pm
x=11y+4
2x = 24y+2


since the question stem asks 13y...24y and 11 y beg us!! PLEASE SUBSTRACT US FROM EACH OTHER! :)

-x = -11y-4
2x= 24y+2

+
----------------

x=13y-2
LGTCH
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by vishubn » Wed Dec 17, 2008 7:06 pm
X=11Y+4---(1)
2X=24Y+2--(2)

(2)-(1)

X=13Y-2

OA D

53 SECS :)

VISHU
KILL !! DIE !! or BEAT my FEAR !!! de@D END!!

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by vittalgmat » Wed Dec 17, 2008 7:44 pm
that was easy.. to solve ..
under 1 min.
I guess this is a 550 level Q ??

Brent: pls give us the tough ones!!..