Aptitude - Numbers - Discussion

Discussion Forum : Numbers - General Questions (Q.No. 31)
31.
On dividing a number by 5, we get 3 as remainder. What will the remainder when the square of the this number is divided by 5 ?
0
1
2
4
Answer: Option
Explanation:

Let the number be x and on dividing x by 5, we get k as quotient and 3 as remainder.

    x = 5k + 3

    x2 = (5k + 3)2

   = (25k2 + 30k + 9)

   = 5(5k2 + 6k + 1) + 4

On dividing x2 by 5, we get 4 as remainder.

Discussion:
37 comments Page 4 of 4.

Mohammed said:   8 years ago
How could come 30 k in above equation?

Ashi said:   9 years ago
@Nil.Dhongde.

The answer is 1.

Sanju said:   1 decade ago
Thanks Neha for easy shortcut.

Lopa said:   1 decade ago
Thanks rajesh for this method.

Kamila Banu said:   4 years ago
= 3 * 3 = 9.
= 9 - 5 = 4.

Narendra said:   1 decade ago
Thanks for the shortcut.

Pema said:   5 years ago
Thank you @Neha Nagar.


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