Adam's age is a multiple of 5 this year.
His age 3 years ago is a multiple of 4.
Adam's age is between 10 and 20.
- What is Adam's age this year?
- What is Adam's age 9 years ago?
- What is Adam's age 9 years later?
Multiple of 5: 5, 10, 15
Multiple of 5 (-3): 2, 7, 12
Multiples of 4: 4, 8, 12
12 appears in both the multiples of 5 (-3) and the multiples of 4.
(a) Adam's age this year = 15
(b) Adam's age 9 year ago = 15 - 9 = 6
(c) Adam's age 9 years later = 15 + 9 = 24
Answer(s): (a) 15; (b) 6; (c) 24