Adam's age is a multiple of 9 this year.
His age next year will be multiple of 4.
Adam's age is between 20 and 30.
- In how many years' time will Adam's age be a multiple of 10?
- How many years ago was Adam's age a multiple of 10?
(a)
Multiples of 9 (between 20 and 30): 27
Multiples of 9 (+1): 19, 28
Multiples of 4: 20, 24, 28
Adam's age next year: 28Adam's age this year: 27Multiples of 10: 10, 20, 30
Adam's age when it becomes a multiple of 10 = 30
Number of years' time when Adam's age will be a multiple of 10
= 30 - 27
= 3
(b)
Multiple of 10: 10, 20
Least number of years ago when Adam's age was a multiple of 10
= 27 - 20
= 7
Answer(s): (a) 3; (b) 7