Adam's age is a multiple of 8 this year.
His age 2 years ago was a multiple of 9.
Adam's age is between 50 and 60.
- 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)
Multiple of 8: 8, 16, 24, 32, 40, 48, 56
Multiple of 8 (-2): 6, 14, 22, 30, 38, 46, 54
Multiples of 9: 9, 18, 27, 36, 45, 54
Adam's age this year = 56
Multiples of 10: 10, 20, 30, 40, 50, 60
Number of years' time when Adam will be a multiple of 10
= 60 - 56
= 4
(b)
Multiples of 10: 10, 20, 30, 40, 50
Least number of years ago when Adam's age was a multiple of 10
= 56 - 50
= 6
Answer(s): (a) 4; (b) 6