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:
46 comments Page 3 of 5.
Sakshi said:
8 years ago
Thanks for the explanation @KCS.
Aaff said:
7 years ago
Thank you for the answer @Anusha.
Harshit said:
7 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.
Vamsikrishnareddy said:
7 years ago
I am not getting this, please anyone explain me in detail.
Chitta meher said:
6 years ago
How come 10 here? Please explain.
Ajeya said:
8 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.
Shalini said:
2 decades ago
Why are we choosing 2x?
Nagendra said:
2 decades ago
Once u find x then try this method to get the answer
21X-12X
21(4)-12(4)
84-48
that means the two number are 84 and 48..
now we have to take the sum of one no and the difference of other no.. according to question sum of digits and difference of digits
that is
48=4+8=12(sum of digits)
84=8-4=4(diff of digits)
now the difference of these two answer
12-4=8
Hence the answer is 8.
21X-12X
21(4)-12(4)
84-48
that means the two number are 84 and 48..
now we have to take the sum of one no and the difference of other no.. according to question sum of digits and difference of digits
that is
48=4+8=12(sum of digits)
84=8-4=4(diff of digits)
now the difference of these two answer
12-4=8
Hence the answer is 8.
Santosh said:
2 decades ago
Why we have to take 2x in units place rather than x ? can any one explain.
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.
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