Correct Answer: ans: 8.

Explanation:

Let, Tenth position digit =X and Unit position digit = y

Number = 10x + y

According to the questions(10x +y) – (10y + x) = 36

=> 10x+y-10y-x =36

=> 9x – 9y = 36x-y= 4……………….. (i)

Again, 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.

y : x = 1 : 2

=> x : y = 2 : 1

=> $\frac{X}{Y}$ = 2

=> x = 2y

x – 2y = 0 …………….(ii)

Solving (i) and (ii) we get: x = 8, y = 4

Sum of the digit 8 + 4 = 12

Difference of the digit 8 – 4 = 4

Difference = 8

Alternative:

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, according to the question(10 x 2x + x)-(10x + 2x)=36

=> 9x = 36x = 4.

Required difference = (2x + x) – (2x – x) = 2x = 8.