Adam's age is a multiple of 9 this year.
His age 6 years ago was a multiple of 8.
Adam's age is between 50 and 60.
- In how many years' time will Adam's age be a multiple of 8?
- How many years ago was Adam's age a multiple of 10?
(a)
Multiple of 9: 9, 18, 27, 36, 45, 54
Multiple of 9 (-6): 3, 12, 21, 30, 39, 48
Multiples of 8: 8, 16, 24, 32, 40, 48
Adam's age this year = 54
Multiples of 8: 8, 16, 24, 32, 40, 48, 56
Number of years' time when Adam will be a multiple of 8
= 56 - 54
= 2
(b)
Multiples of 10: 10, 20, 30, 40, 50
Least number of years ago when Adam's age was a multiple of 10
= 54 - 50
= 4
Answer(s): (a) 2; (b) 4