David's age is a multiple of 7 this year. His age next year will be a multiple of 5. David is more than 40 years old. What is David's age this year?
Multiples of 7: 7, 14, 21, 28, 35, 42, 49
Multiples of 7 (+1): 8, 15, 22, 29, 36, 43, 50
Multiples of 5: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50
Common number = 50
David's age this year
= 50 - 1
= 49
Answer(s): 49
