Adam's age is a multiple of 10 this year.
His age 5 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 8?
- How many years ago was Adam's age a multiple of 3?
(a)
Multiple of 10: 10, 20, 30, 40, 50
Multiple of 10 (-5): 5, 15, 25, 35, 45
Multiples of 9: 9, 18, 27, 36, 45
Adam's age this year = 50
Multiples of 8: 8, 16, 24, 32, 40, 48, 56
Number of years' time when Adam will be a multiple of 8
= 56 - 50
= 6
(b)
Multiples of 3: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48
Least number of years ago when Adam's age was a multiple of 3
= 50 - 48
= 2
Answer(s): (a) 6; (b) 2