Question

A number of two-digits exceed four times the sum of its digit by 3.If 36 is added to the number,the digits are reversed.find the number

Answer 1

let the tens digit of the number be x
let the unit digit of the number be y
so the number is 10x+y

10x+y = 4(x+y) + 3
6x - 3y = 3
2x - y = 1

10x+y + 36 = 10y + x
9x - 9y = -36
x - y = -4

subtract them:
x = 5
then 5 - y = -4
y = 9

the number is 59

check:
4 times the sum of its digits = 4(5+9) = 56, which exceed the number by 3
36 added to 59 = 95, which is the number reversed.

the number is 59