Aptitude - Problems on Numbers - Discussion
Discussion Forum : Problems on Numbers - General Questions (Q.No. 4)
4.
The difference between a two-digit number and the number obtained by interchanging the digits is 36. What is the difference between the sum and the difference of the digits of the number if the ratio between the digits of the number is 1 : 2 ?
Answer: Option
Explanation:
Since the number is greater than the number obtained on reversing the digits, so the ten's digit is greater than the unit's digit.
Let ten's and unit's digits be 2x and x respectively.
Then, (10 x 2x + x) - (10x + 2x) = 36
9x = 36
x = 4.
Required difference = (2x + x) - (2x - x) = 2x = 8.
Discussion:
45 comments Page 3 of 5.
Aaff said:
6 years ago
Thank you for the answer @Anusha.
Sakshi said:
7 years ago
Thanks for the explanation @KCS.
Chitta meher said:
5 years ago
How come 10 here? Please explain.
Sarita said:
7 years ago
Thank you for the answer @Anju.
Karthik said:
5 years ago
X is in units position and why is in ten's position. So the answer should be 16.
Ajeya said:
7 years ago
Lets assume n1=10a+b and n2 = a+10b where a and b are digits in a two digit number,given n1-n2 = 36,
So, 10a+b-a-10b = 36,
9a-9b = 36,
a-b = 4.
How can it be 8? Please help.
So, 10a+b-a-10b = 36,
9a-9b = 36,
a-b = 4.
How can it be 8? Please help.
Abi said:
7 years ago
Where is the 9 from? Please explain.
Anshu 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
Let,
x = 2a
y = a
Then,
a = 4
Difference =
(8 + 4) - ( 8 - 4)
12 - 4 = 8
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
Let,
x = 2a
y = a
Then,
a = 4
Difference =
(8 + 4) - ( 8 - 4)
12 - 4 = 8
Pavithra said:
2 decades ago
I get the answer as 16.
Diff in digits: (x+y)-(x-y)
=2y
=2(2x)
=4x.
Finding the value of x we get, x=4;
So ans = 4(4) = 16.
Diff in digits: (x+y)-(x-y)
=2y
=2(2x)
=4x.
Finding the value of x we get, x=4;
So ans = 4(4) = 16.
Santosh said:
1 decade ago
Why we have to take 2x in units place rather than x ? can any one explain.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers