Adam's age is a multiple of 8 this year.
His age 7 years ago was a multiple of 5.
Adam's age is between 30 and 40.
- 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 6?
(a)
Multiple of 8: 8, 16, 24, 32
Multiple of 8 (-7): 1, 9, 17, 25
Multiples of 5: 5, 10, 15, 20, 25
Adam's age this year = 32
Multiples of 10: 10, 20, 30, 40
Number of years' time when Adam will be a multiple of 10
= 40 - 32
= 8
(b)
Multiples of 6: 6, 12, 18, 24, 30
Least number of years ago when Adam's age was a multiple of 6
= 32 - 30
= 2
Answer(s): (a) 8; (b) 2