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 ?
4
8
16
None of these
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 1 of 5.

Sirjan said:   3 months ago
As ratio of the numbers is 1:2 and it's 2 digit number so possible numbers are only - 12, 24, 36 and 48.

Among those 48 and 84 (reversed 48) gives difference of 36.

So, the digit is 48.

The sum of digits, 8 + 4 = 12
Difference of digits, 8 - 4 = 4
Required difference. 12 - 4 = 8.
(8)

KHY said:   9 months ago
So after devoting 30 min, finally I got this! Hopes this will help you all.

Let's take a two-digit no. = XY( 10x +y)

Imp =suppose 27=2 @tenth +7 @unit)

Ist condition:
Ratio is 1:2
Let's assume x = a.
Y= 2a.

10x+y = 10 *a +2a = 10a + 2a = 12a --->(1)
10y+x = 10 * 2a +a =20a + a = 21a ---> (2).

Difference between.
21a - 12a = 36,
9a = 36,
a = 4.

So,
Fill the value in (1,(2).
I.e. 12a =12*4 = 48
21a = 21*4 = 84.
Sum of digits=4 +8 = 12.
Difference = 8-4 = 4.
Differ. between sum and subtraction,
12-4 = 8.
Hope, I am able to explain you simply as possible.
(34)

Swamy said:   1 year ago
Let's assume 2 digit number is 10.

10x - 01x = 36,
9x = 36,
x = 4.
Coming to question; 1:2;
1x:2x.
1x4: 2x4.
4:8.
Then the answer is 8.
(20)

Maganizo Chithila said:   3 years ago
Ratio is 1:2

we will consider 1 and 2 as the numbers.
And have variable x after the subtracting.
then (21 -12)x=36.

Then 9x=36

And x=4 .

And have 2x for the second number which is 8.
the difference is 8-4 = 4.
the sum of 8+4 = 12.

Therefore the difference is 12-4 = 8.
(12)

Bhargavi said:   3 years ago
From 3rd question,we can say x-y=4.

We have to find diff of ( sum of digits n diff of digits).
(X+y)-(x-y)=0.
X+y=4.
From 2 equations,we get X=4, sub X value then y=0,
So 2 numbers are 40 and 04,
Sum is 44,diff is 36.
So, diff is 44 - 36 = 8.
(6)

Sivasankaran said:   4 years ago
The given number is 36 which is +ve So the original number should be greater
Ex:
If ab is two-digit number b is in unit place and a is in 10th place (.etc..hundreds, tens, units)

Now the given ratio is 1:2 says that the ratio between 10s or 1s
The first number must greater than the reverse digit number.
So we give 2x in 10th place in the first number.
(Number)(10*2x+x)-(Reverse no-Small)(10x+2x)=36.
By solving X=4.

Then they said to find the sum and diff of number.
Ans=(2x+x)-(2x-x).
By solving;
We get the Ans is 8.
(4)

Md Parvez Islam said:   4 years ago
Thanks @Chinnadurai.
(1)

Karthik said:   4 years ago
X is in units position and why is in ten's position. So the answer should be 16.

Chitta meher said:   4 years ago
How come 10 here? Please explain.

Kolkata said:   4 years ago
I am not understanding it, please someone explain me.
(1)


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