BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Please Help Gmat Prep qs.

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Data Sufficiency |
Legendary Member
Posts: 2467
Joined: Thu Aug 28, 2008 6:14 pm
Thanked: 331 times
Followed by:11 members

by cramya » Tue Dec 09, 2008 10:16 pm
n/7 = q+r

n = 7q+r (q->quotient r->remainder)


Whats is r? (could be 0,1,2,3,4,5,6)

Stmt I

n/21 is odd integer(1,3,5,7....)

Consider remainder =1 ,3 case

n/21 = q+1 or n/21 = q + 3 and so on....

n=21q+1 or n= 21q+3
Take q=0

n=1 or n=3

Divide by 7 gives 2 remainder values

INSUFF

Stmt II

n/28 = q+3

n=28q+3

q=0 n=3 3/7 remainder 3
q=1 n = 31 31/7 remainder 3
q=2 n=59 59/7 remainder 3
q=3 n = 87 87/7 remainder 3


It follows a pattern where the remainder will always be 3

ONE DEFINITE ANSWER

SUFF

B)



Regards,
Cramya
Top
Legendary Member
Posts: 1035
Joined: Wed Aug 27, 2008 10:56 pm
Thanked: 104 times
Followed by:1 members

by scoobydooby » Tue Dec 09, 2008 10:23 pm
i had an idea. if a number say a when divided by b leaves a remainder r, then a when divided by any factor of b will leave the same remainder r. can we apply this as a rule?

in the above: n/28 left a remainder 3. so 7 is a factor of 28. so n/7 would also leave 3 as remainder, as would n/2, n/4, n/14 etc
Top
Legendary Member
Posts: 2467
Joined: Thu Aug 28, 2008 6:14 pm
Thanked: 331 times
Followed by:11 members

by cramya » Tue Dec 09, 2008 10:25 pm
I had an idea. if a number say a when divided by b leaves a remainder r, then a when divided by any factor of b will leave the same remainder r. can we apply this as a rule?
U read my mind. I was about to post it and leave it open for other comments.

The only thing I would add is factors that are greater than the remainder in question( i.e 3 in this problem) .

Eg: 28 has 6 factors 1,2,4,7,14,28

If u look at 4,7,14,28 all leave a remainder 3 for the same n

2 leaves a remainder 1

1 leaves a remainder 0

Regards,
Cramya
Top
Legendary Member
Posts: 1035
Joined: Wed Aug 27, 2008 10:56 pm
Thanked: 104 times
Followed by:1 members

by scoobydooby » Tue Dec 09, 2008 10:32 pm
thanks cramya. got it.
Top
Legendary Member
Posts: 2467
Joined: Thu Aug 28, 2008 6:14 pm
Thanked: 331 times
Followed by:11 members

by cramya » Tue Dec 09, 2008 10:34 pm
thanks cramya. got it.

No problem; good luck with ur prep Scoobydooby!

Nice thinking on your part also!
Top
Senior | Next Rank: 100 Posts
Posts: 33
Joined: Mon Nov 17, 2008 12:08 pm
Thanked: 1 times

by NehaBhandari » Wed Dec 10, 2008 9:05 am
Thnks guys.. appreciate ur help..
Top
User avatar
Legendary Member
Posts: 546
Joined: Sun Nov 16, 2008 11:00 pm
Location: New Delhi , India
Thanked: 13 times

by ronniecoleman » Wed Dec 10, 2008 9:06 am
Nice question:

Given

N = 7 * K + r -----------{1}

r CANNOT be greater than 7


option: 2

N = 28 m + 3 ------------{2}

28m + 3 = 7*K + r

r = 7* t + 3

r = { 3, 10, 17 , ...)

but r should be less than 7 so r is 3

Option 1

r = 7*t + ODD no.

which can be 5 or 3
Admission champion, Hauz khaz
011-27565856
Top
Legendary Member
Posts: 574
Joined: Sun Jun 01, 2008 8:48 am
Location: Bangalore
Thanked: 28 times

by vishubn » Wed Dec 10, 2008 9:19 am
from the stem we know we have to find out the remainder when divided by 7 !

A) its an odd number ! number can be 23,25,27 all divided by 21 gives odd number

B)n=31 31/28=3
n=59 59/28=3

31/7 remainder is 3

59/3 again fetches u 3

B it is
KILL !! DIE !! or BEAT my FEAR !!! de@D END!!
Top
Post new topic Post Reply
• Page 1 of 1