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If x and y are positive intergers, what is the remainder

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If x and y are positive intergers, what is the remainder [#permalink] If x and y are positive intergers, what is the remainder   19 Feb 2011, 11:13
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If x and y are positive intergers, what is the remainder when 10^x+y is divided by y?

(1) x=5
(2) y=2
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B
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Bunuel
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Re: Remainder [#permalink] If x and y are positive intergers, what is the remainder   19 Feb 2011, 11:22
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Baten80
If x and y are positive intergers, what is the remainder when 10^x+y is divided by y?

(1) x=5
(2) y=2

\(\frac{10^x+y}{y}=\frac{10^x}{y}+1\) --> so we basically need the remainder upon division 10^x by y (as in 10^x+y the second term y is divisible by y itself then only the first term matters for remainder).

(1) x=5 --> need the value of y. Not sufficient.
(2) y=2 --> as x is a positive integer then 10^x is an even number and 10^x=even divided by 2 yields the remainder of zero. Sufficient.

Answer: B.
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Re: If x and y are positive intergers, what is the remainder [#permalink] If x and y are positive intergers, what is the remainder   15 Aug 2013, 21:21
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REM[10^(x+y)]/y

(1) x=5

REM[10^(5+y)]/y no information about y so REM is not consistent hence INSUFFICIENT.

(2) y=2

REM[10^(x+2)]/2

Any power of 10 is even => Divisible by 2 => REM =0

Hence SUFFICIENT

Hence (B) !
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If x and y are positive intergers, what is the remainder [#permalink] If x and y are positive intergers, what is the remainder   Updated on: 17 May 2021, 08:36
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Baten80
If x and y are positive integers, what is the remainder when \(10^x + y\) is divided by y?

(1) x = 5
(2) y = 2

Given: x and y are positive integers

Target question: What is the remainder when \(10^x + y\) is divided by y?

Statement 1: x = 5
Since we have no information about y, we cannot answer the target question with certainty
Statement 1 is NOT SUFFICIENT

Statement 2: y = 2
Important: When we divide an integer by 2, the remainder will be EITHER 1 OR 0, depending on whether the integer is odd or even.
If the number is ODD, then we get a remainder of 1 after dividing by 2
If the number is EVEN, then we get a remainder of 0 after dividing by 2

Now that we know the value of y, our target question becomes, "What is the remainder when \(10^x + 2\) is divided by 2?"
Since \(10^x\) is EVEN for all positive integer values of x, we know that \(10^x + 2\) must be EVEN

So, our target question becomes, "What is the remainder when SOME EVEN NUMBER is divided by 2?"
The answer to this new target question is the remainder will be 0
Since we can answer the target question with certainty, statement 2 is SUFFICIENT

Answer: B

Cheers,
Brent

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Originally posted by BrentGMATPrepNow on 12 Mar 2020, 08:00.
Last edited by BrentGMATPrepNow on 17 May 2021, 08:36, edited 1 time in total.
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Re: If x and y are positive intergers, what is the remainder [#permalink] If x and y are positive intergers, what is the remainder   14 Oct 2020, 19:38
If x and y are positive intergers, what is the remainder when 10^x+y is divided by y?

Prior to looking at the items, I would first separate the 10^x and 10 ^y and divide them by y as shown below.

(10^x)(10^y)/y

This will tell us that if y is divisible by either item we would know that y is a divisor with no remainder.

(1) x=5
Tells us nothing about the divisor y.

(2) y=2

10^2 is even and divisible by 2. sufficient!
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Re: If x and y are positive intergers, what is the remainder [#permalink] If x and y are positive intergers, what is the remainder   19 Oct 2023, 05:45
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Re: If x and y are positive intergers, what is the remainder [#permalink]
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