Adam's age is a multiple of 7 this year.
His age 5 years ago was a multiple of 10.
Adam's age is between 30 and 40.
- In how many years' time will Adam's age be a multiple of 6?
- How many years ago was Adam's age a multiple of 3?
(a)
Multiple of 7: 7, 14, 21, 28, 35
Multiple of 7 (-5): 2, 9, 16, 23, 30
Multiples of 10: 10, 20, 30
Adam's age this year = 35
Multiples of 6: 6, 12, 18, 24, 30, 36
Number of years' time when Adam will be a multiple of 6
= 36 - 35
= 1
(b)
Multiples of 3: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33
Least number of years ago when Adam's age was a multiple of 3
= 35 - 33
= 2
Answer(s): (a) 1; (b) 2