Aptitude - Numbers - Discussion

Discussion Forum : Numbers - General Questions (Q.No. 69)
69.
n is a whole number which when divided by 4 gives 3 as remainder. What will be the remainder when 2n is divided by 4 ?
3
2
1
0
Answer: Option
Explanation:

Let n = 4q + 3. Then 2n = 8q + 6   = 4(2q + 1 ) + 2.

Thus, when 2n is divided by 4, the remainder is 2.

Discussion:
15 comments Page 1 of 2.

Tejas said:   4 years ago
If n=19 then 2n = 38.

2n/4=38/4 (here remainder is 2) =19/2 (here remainder is 1).

Why does remainder change for the same fraction? Please explain me.

Janardhan jada said:   5 years ago
I can't understand please explain this step by step.

Bindu said:   6 years ago
Assume n to be any number such that when it is divided by 4 we should get 3 as R.

So let n be 15 (when 15/4, R=3, condition satisfied as per in the given question).

Therefore 2n will be 30. (when 30/4, R=2, the required answer).
(5)

Naina said:   7 years ago
The equation be like;

n=4*q+3 (let us assume q=1)
n=4+3
n=7.

Next equation is;
2n=4*q+x (q=1,assumed).
2(7)=4+x,
14/4 = x,
The remainder 2.
(1)

Shweta said:   7 years ago
Lt quotient be q and R be remainder.

n=4q+3 ---> eqn(1)
2n=4q+R ---> eqn(2)

therefore, putting eqn(1) in eqn (2);

2(4q+3) = 4q+R.
8q+6 = 4q + R,
let q=1,
4+6=R,
10 = R,
when 10 is divided by 4;
R=2.
(2)

Deepika nair said:   7 years ago
I coulnt understand this concept. Could you please help me?

Naina said:   7 years ago
Explain it clearly?

Kannan said:   7 years ago
Here;
n reminder is 3.
2n/4=?
substitute n value 3,
2(3)/4=6/4.
6/4=2.

Gautham said:   8 years ago
Why it can't be like this:
n = 4q+3..... eq-01.
2n = 4q+X...eq-02.

Putting eq-01 in eq-02,
2(4q+3) = 4q+X.
8q+6 = 4q+X.
X = 4q+6.
X = 2*(2q+3).

Remainder should be 3 I don't know why they are taking 2.
(1)

Ishwariya said:   8 years ago
I can't able to understand. Please explain it clearly.


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