Question

The sum of my digits is an even number. My first digit is 6 less than my second digit. 12 is the number you get when you add my digits. What number am I?

Answer 1

39

Explanation:

Let a and b represent the first and second digits, respectively.

... a = b -6 . . . . . . the first digit is 6 less than the second

... a + b = 12 . . . . .the sum of digits is 12 (an even number)

Using the expression in the first equation, we can substitute for a in the second equation:

... (b -6) +b = 12

... 2b = 18 . . . . . . add 6, simplify

... b = 9 . . . . . . . . .divide by 2

... a = 9 -6 = 3 . . . . from the first equation

The number is 39.