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 ?
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.
Amit said:
1 decade ago
x/5 = 3.
Square of (x/5)/5 = 9/5 = 4.
Square of (x/5)/5 = 9/5 = 4.
Sanju said:
1 decade ago
Thanks Neha for easy shortcut.
Neha nagar said:
1 decade ago
For this kind of question consider any no. Suppose 13/5 gives remainder 2 then the square of 13 means 169 when divided by 169 gives remainder 4.
Kiran said:
1 decade ago
Let the num is 3. Then square of 3 is 9 so 9/5 remainder is 4.
Lopa said:
1 decade ago
Thanks rajesh for this method.
Narendra said:
1 decade ago
Thanks for the shortcut.
Rajesh rao.v said:
2 decades ago
X = 5+3 = 8 square of 8 = 64 then 64/5 remainder is 4.
(1)
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