ak_idc wrote:

cicerone wrote:

Folks, again this is simple if u know the basic concepts of remainders.

Let's look at this simple problem first.

Remainder obtained when 11xK is divided by 4 is nothing but the remainder obtained when 11 is divided by 4 x K divided by 4

ie the remainder of 11xK / 4 will be of the form 3xK (in case 3xK is greater than 4 it will be further divided by 4 to get the remainder)

Similarly when 11xK + 17 is divided by 9 the remainder will of the form 2xK + 8.

Using this concept to the given problem

4+7n/3 the remainder will be of the form 1 + n. ( So the remainder now depends upon the value of n)

Statement 1: Since it is given that n+1 is divisible by 3.

Hence 4 + 7n / 3 the remainder will be 0.

So statement 1 alone is sufficient.

Statement 2: n > 20.

For different values of n we get different remainders.

So statement 2 is not sufficient

Hence A.

Regards,

Cicerone, why are you taking 3 and 2? and not 2 and 1? Can you pls clarify?

Hey dear,

when 11 is divided by 4 the reamainder is 3

So 11k divided by 4 the remainder will be of the form 3k

Similary 11 divided by 9 the remainder is 2

So 11k divided by 9 the remainder will be of the form 2k

Let me be more clear

Let's take 45. When 45 is divided by 8 the remainder is 5

Now 45 = 9 x 5

Now 9 leaves a remainder 1 when divided by 8

and 5 leaves a remainder 5 when divided by 5.

Since 45 = 9 x 5

The remainder also will be remainder of 9/8 x remainder of 5/8

ie 1 x 5 = 5

Let's take another example

2272/6 the raminder is 4

Now 2272 = 32 x 71

32/6 the remainder is 2

71/6 the remainder is 5

So according to our rule the remainder must be 2 x 5 = 10

Since 10 is greater than 6 it is further divided and hence the remainder becomes 4.

So all the three basic operations i.e additon, subtraction and multiplication of remainders can be done.

i.e Remainder of 45k + 23p - 17q when divided by 12 will take the form of 9k + 11p - 5q.

I think this is clear to everyone

Regards,