Adam was 3 times as old as Bryan 30 years ago.
Their total present age is 100 years now.
- How old is Adam now?
- How many years is Adam older than Bryan?
- How old is Bryan in 15 years' time?
|
Adam |
Bryan |
Total |
30 years ago |
3 u |
1 u |
4 u |
Change |
+ 30 |
+ 30 |
+ 60 |
Present |
3 u + 30 |
1 u + 30 |
100 |
(a)
Total age of Adam and Bryan 30 years ago
= 100 - 60
= 40
30 years ago
Adam's age = 3 u
Bryan's age = 1 u
Total age of Adam and Bryan = 4 u
4 u + 60 = 100
4 u = 100 - 60 = 40
1 u = 40 ÷ 4 = 10
Adam's age now
= 3 u + 30
= 3 x 10 + 30
= 30 + 30
= 60
(b)
Number of years that Adam is older than Bryan
= 3 u - 1 u
= 2 u
= 2 x 10
= 20
(c)
Bryan's age in 15 years' time
= 1 u + 30 + 15
= 10 + 30 + 15
= 55
Answer(s): (a) 60; (b) 20; (c) 55