Aptitude - Problems on Numbers - Discussion
Discussion Forum : Problems on Numbers - General Questions (Q.No. 3)
3.
The difference between a two-digit number and the number obtained by interchanging the positions of its digits is 36. What is the difference between the two digits of that number?
Answer: Option
Explanation:
Let the ten's digit be x and unit's digit be y.
Then, (10x + y) - (10y + x) = 36
9(x - y) = 36
x - y = 4.
Video Explanation: https://youtu.be/7QOJjAmGVx0
Discussion:
59 comments Page 1 of 6.
Devshree vaidya said:
2 years ago
According to me.
The two-digit number I'll take is 10.
And subtract with 36.
So I'll get 26.
Then I have to find the difference between the two-digit number so I'll subtract 2-6 =4 so the answer is 4.
The two-digit number I'll take is 10.
And subtract with 36.
So I'll get 26.
Then I have to find the difference between the two-digit number so I'll subtract 2-6 =4 so the answer is 4.
(20)
Haider alam said:
7 years ago
Let the unit place be x.
Ten =10x.
On interchanging position in difference.
10x-x=39,
9x=36,
x=36/9,
x = 4 answer.
Note : If we don't interchange the value of x will be -4.
Ten =10x.
On interchanging position in difference.
10x-x=39,
9x=36,
x=36/9,
x = 4 answer.
Note : If we don't interchange the value of x will be -4.
(7)
Megha said:
1 year ago
@All.
Now for example;
Take the number to be 54(example), then in units place we have 4 and in tens place we have 5
Separately,
x = 5
y = 4
For xth place 10*5=50
For yth place. +4
= 54
Hence 10*x + y ---->(1)
After interchanging in xth place we have y so,
10*y + x -----> (2)
So that's why we have 10.
Now for example;
Take the number to be 54(example), then in units place we have 4 and in tens place we have 5
Separately,
x = 5
y = 4
For xth place 10*5=50
For yth place. +4
= 54
Hence 10*x + y ---->(1)
After interchanging in xth place we have y so,
10*y + x -----> (2)
So that's why we have 10.
(5)
Sri said:
1 decade ago
Let x and y be two digits of the Numbers.
Such that x is in tens position and y is at the ones place.
So xy is the number,
xy = 10(x) + y(1) ----------> (1).
On interchanging the digits we get,
yx = y(10) + x(1) ----------> (2).
(10x + y) - (10y + x)= 36.
10x + y - 10y - x = 36.
9x - 9y = 36.
x - y = 4.
This explanation is super @Anshu.
Such that x is in tens position and y is at the ones place.
So xy is the number,
xy = 10(x) + y(1) ----------> (1).
On interchanging the digits we get,
yx = y(10) + x(1) ----------> (2).
(10x + y) - (10y + x)= 36.
10x + y - 10y - x = 36.
9x - 9y = 36.
x - y = 4.
This explanation is super @Anshu.
(5)
Udaya said:
4 years ago
The question is that interchanging position.
Where did they ask 10th digit place?
Please explain me.
Where did they ask 10th digit place?
Please explain me.
(5)
Jeevan said:
6 years ago
Here, it is given the number obtained by interchanging the position 2 digit number not 1 digit number like 93 - 39 = 36.
(4)
Kama gupta said:
9 years ago
By trick,
For difference = d/9 and for sum = s/11.
So,
Difference = 36/9 = 4 (answer).
For difference = d/9 and for sum = s/11.
So,
Difference = 36/9 = 4 (answer).
(2)
Mohankumar said:
1 decade ago
To overcome like this problems, you have to know very basic thing i.e how do we expand a number??
eg, 345=3*100+4*10+5*1 right?
So now assume digits as xy then u expand it x*10+y*1=xy;
Similar way interchange digits xy-->yx isn't it?
So expand yx=y*10+x*1;
Now you xy-yx=36;(put expanded form in this);
Simplify it..
eg, 345=3*100+4*10+5*1 right?
So now assume digits as xy then u expand it x*10+y*1=xy;
Similar way interchange digits xy-->yx isn't it?
So expand yx=y*10+x*1;
Now you xy-yx=36;(put expanded form in this);
Simplify it..
(2)
Anoj said:
6 years ago
How can it solve using only one variable?
(1)
Shams said:
1 decade ago
Hi,
There is not taking 10 digit number. that is the 10th place of number we are finding. see
There are 2 two digit is let x and y,
So the number will be 10x+y (x is at tenth position & y is at unit position)
Because for example number 85.
x=8 and y=5.
So, 10x+y = ( 10 * 8 + 5 = 85 ).
Not do the number (xy = 8*5 = 40) or (10xy = 10*8*5 =400 ).
Now for answer proceed further according to question.
I think its help to you.
There is not taking 10 digit number. that is the 10th place of number we are finding. see
There are 2 two digit is let x and y,
So the number will be 10x+y (x is at tenth position & y is at unit position)
Because for example number 85.
x=8 and y=5.
So, 10x+y = ( 10 * 8 + 5 = 85 ).
Not do the number (xy = 8*5 = 40) or (10xy = 10*8*5 =400 ).
Now for answer proceed further according to question.
I think its help to you.
(1)
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers