Question

A two digit number is such that the sum of its digits is 4 if 18 is added to the number it's digits are reversed find the number

Answer 1

Best Answer: let x and y be the digit, then the number is 10x+y.
x + y = 4
10x + y + 18 = 10y + x
9x - 9y = -18
9(x - y) = -18
x - y = -2

x + y = 4
x - y = -2
2x = 2
x = 1
y = 3

number is 10x+y=10+3=13