Question

the sum of digits of a two digit number is 12 the number obtained by interchanging the digits exceeds the given number by 18.find the number

Answer 1

I hope it will help you

Answer 2

let the number be xy.
this number is represented as 10x+y.
sum of digits of number is x+y.
x+y=12...eq 1
10y+x= 10x+y+18 ....eq2
on simplifies the equation we get
x+y=12 ...eq3
-9x+9y=18 or -x+y= 2...eq4
on substitution of the value of y=x+2 from eq4 into eq3
x+x+2=12
2x=12-2
x=5
substitute the value of x into eq 4
5+y=12
y=7
so the number is 57.
let's check it is correct or not
5+7=12
75= 57+18
so answer is correct.the number is 57.