Adam's age is a multiple of 4 this year.
His age next year will be multiple of 5.
Adam's age is between 40 and 50.
- In how many years' time will Adam's age be a multiple of 7?
- How many years ago was Adam's age a multiple of 5?
(a)
Multiples of 4 (between 40 and 50): 40, 44, 48
Multiples of 4 (+1): 33, 37, 41, 45, 49
Multiples of 5: 40, 45, 50
Adam's age next year: 45Adam's age this year: 44Multiples of 7: 35, 42, 49
Adam's age when it becomes a multiple of 7 = 49
Number of years' time when Adam's age will be a multiple of 7
= 49 - 44
= 5
(b)
Multiple of 5: 30, 35, 40
Least number of years ago when Adam's age was a multiple of 5
= 44 - 40
= 4
Answer(s): (a) 5; (b) 4