Adam's age is a multiple of 5 this year.
His age next year will be multiple of 7.
Adam's age is between 50 and 60.
- In how many years' time will Adam's age be a multiple of 9?
- How many years ago was Adam's age a multiple of 7?
(a)
Multiples of 5 (between 50 and 60): 50, 55, 60
Multiples of 5 (+1): 41, 46, 51, 56, 61
Multiples of 7: 56
Adam's age next year: 56Adam's age this year: 55Multiples of 9: 45, 54
Adam's age when it becomes a multiple of 9 = 63
Number of years' time when Adam's age will be a multiple of 9
= 63 - 55
= 8
(b)
Multiple of 7: 42, 49
Least number of years ago when Adam's age was a multiple of 7
= 55 - 49
= 6
Answer(s): (a) 8; (b) 6