Adam's age is a multiple of 5 this year.
His age next year will be multiple of 7.
Adam's age is between 20 and 30.
- In how many years' time will Adam's age be a multiple of 6?
- How many years ago was Adam's age a multiple of 8?
(a)
Multiples of 5 (between 20 and 30): 20, 25, 30
Multiples of 5 (+1): 11, 16, 21, 26, 31
Multiples of 7: 21, 28
Adam's age next year: 21Adam's age this year: 20Multiples of 6: 12, 18, 24, 30
Adam's age when it becomes a multiple of 6 = 24
Number of years' time when Adam's age will be a multiple of 6
= 24 - 20
= 4
(b)
Multiple of 8: 16
Least number of years ago when Adam's age was a multiple of 8
= 20 - 16
= 4
Answer(s): (a) 4; (b) 4