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

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

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

thanks cramya. got it.

thanks cramya. got it.

No problem; good luck with ur prep Scoobydooby!

Nice thinking on your part also!

Thnks guys.. appreciate ur help..

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

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