# 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
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 2 of 5.

Hi I could not understand this problem. Can anyone explain this more clearly please?
(1)

Jonsihay said:   9 years ago
The Problem should be re-stated specially on the aspect of the ratio.

It should "NOT JUST BE" 'if the ratio between the digits of the number is 1:2. But it should be restated as 'if the ratio between the unit's and ten's digits of the number is 1:2.

Then if that's ok, I think reliably be solvable!
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Anju said:   6 years ago
Since they have mentioned the word "difference" in the problem so the answer will be 8 .From the 1st part of the question we can find that X-Y=4, also they have mentioned X/Y=1/2 hence Y=2X;

Therefore X~2X=4;hence X=4;Y=8;
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Md Parvez Islam said:   4 years ago
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Hi I can't understand this problem. Any more explnation please.
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It can't b (x+y) - (x-y).

Rather it could be (10x +y) - (10y + x).
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Rajesh jangid said:   8 years ago
Hi can anyone explain when to take 2x and x and when 10x+y-10y-x?

Vamsikrishnareddy said:   5 years ago
I am not getting this, please anyone explain me in detail.

Harshit said:   5 years ago
Correct answer should be 16. Ten's digit is X and Unit digit is 2X as the ratio given is 1:2 and not 2:1.

Aaff said:   5 years ago
Thank you for the answer @Anusha.