The units digit of a 2 digit number exceeds thrice the tens digit by 1. The sum of the digits is 9. Find the number.

Answer 1

27

Answer 2

a = first number

b = second number

b = 3 a + 1

a + b = 9

a + 3 a + 1 = 9

4 a + 1 = 9 Subtract 1 to both sides

4 a + 1 - 1 = 9 - 1

4 a = 8 Divide both sides by 4

a = 8 / 4

a = 2

b = 3 a + 1

b = 3 * 2 + 1

b = 6 + 1

b = 7

Your number :

27