The difference between a two-digit number and the number obtained by interchanging the digits is 54. What is the difference between the sum and the difference of the digits of the number if the ratio of the digits of the number is 3 ∶ 1?

The difference between a two-digit number and the number obtained by interchanging the digits is 54. What is the difference between the sum and the difference of the digits of the number if the ratio of the digits of the number is 3 ∶ 1? Correct Answer 6

Given:

The difference between a two-digit number and the number obtained by interchanging the digits is 54.

The ratio of the digits of the number is 1 ∶ 3.

Calculation:

Let the unit digit of the number be x and tenth digit be y

Then the number = 10x + y

When we interchange the digit of the number, new number = 10y + x

Now, according to question (10x + y) - (10y + x) = 54

⇒ 10x + y - 10y - x = 54

⇒ 9x - 9y = 54

⇒ 9(x - y) = 54

⇒ x - y = 6      ----(1)

It is given that x : y = 3 : 1

Then x = 3y      ----(2)

By (1) and (2),

3y - y = 6

⇒ 2y = 6

⇒ y = 3

So x = 3y

⇒ x = 3 × 3

⇒ x = 9

So, unit digit of the number = x = 9 and tenth digit of the number = 3

Now, sum of the digits = 9 + 3 = 12 and difference of digit = 9 - 3 = 6

∴ Difference between the sum and the difference of the digits of the number is 6. 

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