What is the remainder when the positive integer n is divided

Question

What is the remainder when the positive integer n is divided by 3?

(1) The remainder when n is divided by 2 is 1. 
(2) The remainder when n + 1 is divided by 3 is 2

Bunuel · Accepted Answer

What is the remainder when the positive integer n is divided by 3?

(1) The remainder when n is divided by 2 is 1 -->  n=2k+1 , just tells us that  n  is odd. Not sufficient.

(2) The remainder when n + 1 is divided by 3 is 2 -->  n+1=3q+2  -->  n=3q+1 , hence  n  divided by 3 yields remainder of 1. Sufficient.

Answer: B.

shaselai · Answer

Lets take another approach if you couldnt derive what bunnel did.

1. remainder n/2 =1 
lets try some numbers:
n=3 remainder =1 n/3 remainder =0
n=5 remainder = 1 5/3 remainder =2
So NO FOOD

2. 
n=4 n+1 =5 5/3 =2 4/3 =1
n=7 n+1=8 8/3=2 7/3 =1

Notice how the trend is every 3 for n. so it is working correctly

B

TGC · Answer

n=3A+r

What is r?

(1).

n=2B+1 => N is odd but odd numbers also can give different remainders when divided by 3 .
INSUFFICIENT

(2).

n+1 = 3C +2
n= 3C +1

REM=1

Hence (B) it is !!

Kinshook · Answer

Asked: What is the remainder when the positive integer n is divided by 3?

(1) The remainder when n is divided by 2 is 1. 
n = 2k + 1
If n=1; The remainder when the positive integer n is divided by 3 = 1
If n=3: The remainder when the positive integer n is divided by 3 = 0
If n=5; The remainder when the positive integer n is divided by 3 = 2
The remainder when the positive integer n is divided by 3 = {0,1, 2}
NOT SUFFICIENT

(2) The remainder when n + 1 is divided by 3 is 2
n + 1 = 3k + 2
n = 3k + 1
The remainder when the positive integer n is divided by 3 = 1
SUFFICIENT

IMO B

MHIKER · Answer

(1) n=2q+1;1, 3, 5, 7.. When divided 3 there are different remainders; Insufficient.

(2) n+1=3q+2

Or, n=3q+1; Sufficient.

The answer is B

bumpbot · Answer

Automated notice from GMAT Club BumpBot: 

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

 This post was generated automatically.

What is the remainder when the positive integer n is divided

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Data Sufficiency (DS) Questions

What is the remainder when the positive integer n is divided

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards