Question

the sum of two digit number is 13 if the number is subtracted from the one obtained by interchanging the digits the results is 45 what is the number

Answer 1

let number be ab
a+b=13
10b+a-10a-b=45
9b-9a=45 ,
b-a=5
2b=18 b=9
a=4
no is 49

Answer 2

Here is your solution

Given :-
The sum of two digit number is 13 .
if the number is subtracted from the one obtained by interchanging the digits the results is 45 .

Let
The two digits be x and y.

Number is 10x + y 

x + y = 13 (given)

y = 13 – x --------------1

A/q

10y + x – (10x + y) = 45

9y – 9x = 45

y – x = 5 --------------2

putting the value of y from equation 1 in eqn 2

13 – x – x = 5

13 – 2x = 5

2x = 8

x = 4✔

y = 13 – 4 = 9✔

The two-digit number = 10x + y = (10 × 4) + 9 = 49.

Hope it helps you.