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:
3 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.
(25)
Megha said:
2 years 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.
(7)
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)
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)
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)
Jeevan said:
7 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)
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)
Kama gupta said:
10 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)
Manasa said:
1 decade ago
Explain this step : (10x + y) - (10y + x) = 36
How 10x+y got ?
How 10x+y got ?
(1)
Ayushi Nandy said:
4 years ago
Thanks everyone for explaining the answer.
(1)
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