Riordan's age is a multiple of 5 this year. His age next year will be a multiple of 4. Riordan is more than 30 years old. What is Riordan's age this year?
Multiples of 5: 5, 10, 15, 20, 25, 30, 35
Multiples of 5 (+1): 6, 11, 16, 21, 26, 31, 36
Multiples of 4: 4, 8, 12, 16, 20, 24, 28, 32, 36
Common number = 36
Riordan's age this year
= 36 - 1
= 35
Answer(s): 35