Aptitude - Numbers - Discussion

Discussion Forum : Numbers - General Questions (Q.No. 43)
43.
Which one of the following is the common factor of (4743 + 4343) and (4747 + 4347) ?
(47 - 43)
(47 + 43)
(4743 + 4343)
None of these
Answer: Option
Explanation:

When n is odd, (xn + an) is always divisible by (x + a).

Each one of (4743 + 4343) and (4747 + 4347) is divisible by (47 + 43).

Discussion:
17 comments Page 1 of 2.

Maneesh said:   4 years ago
a^3 + b^3 = (a+b) (a2+b2-ab) is odd and we have to plus, i.e. we can divide by a+b.

Whereas, if n is odd and we have minus, a3-b3 formula i.e divide by a-b.

Vijaybarath said:   4 years ago
Simply;

a3 + b3 = (a+b) (a2+b2-ab) is odd, i.e we can dived by a+b.
Whereas, if even a3-b3 formula i.e divide by a-b.

Praveen said:   5 years ago
How to divide it? Please explain in detail.
(1)

Navneet said:   7 years ago
Can anyone please explain it, what if the value of n is even? Then what will be the common factor?
(3)

Suyog said:   8 years ago
A number which divides two or more number is called common factor of that number.

Ravi kant said:   9 years ago
When power n is odd then (a+b) divide a^n+b^n.
eg: a^3 + b^3 = (a + b)(a^2 - ab + b^2).

And, if power n is even then it divide a^n-b^n.
eg: a^3 - b^3) = (a - b)(a^2 + ab + b^2).
(2)

Simran said:   9 years ago
Can be solved by cyclicity.

Unit place of 1st number is 0 after addition. Which means it is a factor of 10. Out of options only 43 + 47 = 90 is the factor of 10. So, 43 + 47 is the answer.
(2)

Sasikumar said:   9 years ago
Can anyone explain it please?

Naimul said:   9 years ago
(47^43 + 43^43).

= 43^43 (4^43 + 1^43).

Again,

43^47 (4^47 + 1^47).

So, 43^43 * 43^47.

= 43 (43 + 47).

Akshay said:   10 years ago
When the HCF of two no. is 1, this no. is called common factor.

Ex. 72 = 8*9.
8 = 2^3.
9 = 3^2.

The HCF of 8 & 9 is 1. Hence it makes as common factor.


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