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 1 of 4.
Nil.dhongde said:
1 decade ago
@Rajesh rao method is very wrong. It doesn't follow the rules everywhere. This method is like hit and try. The original universal method is given itself in problem.
Wanna check it out if Mr Rajesh rao's method is right or wrong. Try this.
So here is similar problem for those, who used to use other shortcuts method.
if certain number is divided by 7 gives 6 as remainder. What will be the remainder if square of the same number is divided by 7?
Wanna check it out if Mr Rajesh rao's method is right or wrong. Try this.
So here is similar problem for those, who used to use other shortcuts method.
if certain number is divided by 7 gives 6 as remainder. What will be the remainder if square of the same number is divided by 7?
Kums kutty said:
9 years ago
In problem x is divisable by 5 then the remainder is 3 so we have X/5=3 then find x value X = 5 * 3 = 15.
In problem, they mentioned square of X is divisible by 5 then what is the remainder.
So X value is 15 then it's square is 225 now we divide it by 5.
225/5 = 45, 45/5 = 9, 9/5 = 4 as a remainder.
In problem, they mentioned square of X is divisible by 5 then what is the remainder.
So X value is 15 then it's square is 225 now we divide it by 5.
225/5 = 45, 45/5 = 9, 9/5 = 4 as a remainder.
Udaya santhi said:
1 decade ago
The number taken as n.
n = 5*q+3.
The square of the number is n*n=(5q+3)^2.
That number is divisible by 5.
Therefore, [(5q+3)^2]/5={[(5q)^2/5]+[2(5q)(3)/5]}+[9/5].
The flower bracket whole number is divisible by 5. But 9/5 = remainder is 4.
n = 5*q+3.
The square of the number is n*n=(5q+3)^2.
That number is divisible by 5.
Therefore, [(5q+3)^2]/5={[(5q)^2/5]+[2(5q)(3)/5]}+[9/5].
The flower bracket whole number is divisible by 5. But 9/5 = remainder is 4.
Bhuvana ram said:
6 years ago
Formula:(Divisor * Quotient) + remainder = Dividend.
So, (5*Q)+3=D ----> (1)
D^2%5=R -----> (2)
Now we substitute equation(1) in (2).
((5*Q)+3)^2%5 = R
Assume Q = 1,
(5+3)^2%5 = R.
(8)^2%5 = R,
64%5 = R,
4 = R.
So, (5*Q)+3=D ----> (1)
D^2%5=R -----> (2)
Now we substitute equation(1) in (2).
((5*Q)+3)^2%5 = R
Assume Q = 1,
(5+3)^2%5 = R.
(8)^2%5 = R,
64%5 = R,
4 = R.
(2)
Ankita said:
1 decade ago
If we subtract the remainder by number i.e. x - 3 and divide it by 5 we will get zero.
Therefore (x - 3)/5 = 0.
x = 3.
Now 3^2 = 9.
& 9/5 the remainder will be 4.
Therefore (x - 3)/5 = 0.
x = 3.
Now 3^2 = 9.
& 9/5 the remainder will be 4.
Sukesh said:
10 years ago
Consider the two reminders first we got 3 before squaring the number.
After squaring and dividing we got 5 as reminder.
So square the 1st reminder 3^2=9. Then, 9/5=4 is the reminder.
After squaring and dividing we got 5 as reminder.
So square the 1st reminder 3^2=9. Then, 9/5=4 is the reminder.
IKRAMUL said:
7 years ago
The square of this no means 3 *3=9.
And 9/5 rem is for,
Also let a no which divides by 5 rem is 3.
Where 8/5 rem is 3,
The square of this no is 64,
64/5 we get 4 is a rem.
And 9/5 rem is for,
Also let a no which divides by 5 rem is 3.
Where 8/5 rem is 3,
The square of this no is 64,
64/5 we get 4 is a rem.
(1)
Jeevitha said:
1 decade ago
Let the number be x.
x = 5k+3.
Let us take k = 1.
Then x = 5(1)+3.
x = 8.
So, square of 8 = 64.
When 64 is divided by 5.
Remainder is 4.
Therefore, answer is 4.
x = 5k+3.
Let us take k = 1.
Then x = 5(1)+3.
x = 8.
So, square of 8 = 64.
When 64 is divided by 5.
Remainder is 4.
Therefore, answer is 4.
Karthik pyati said:
5 years ago
1step: to add 5+3=8 den divide by 5, will give remainder as 3, then square the remainder number 3 i.e(3^2)=9, when dividing the no 5 & the remainder will be 4.
(1)
Radha gayathri said:
5 years ago
Formula: dividend = divisor * quotient + remainder.
Divisor=5, reamainder=3.
5*q+3.
(5*q+3)^2/5.
Assume q as 1,
(5+3)^2/5,
(8)^2/5,
64/5.
And the remainder is 4.
Divisor=5, reamainder=3.
5*q+3.
(5*q+3)^2/5.
Assume q as 1,
(5+3)^2/5,
(8)^2/5,
64/5.
And the remainder is 4.
(1)
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