Adam was 3 times as old as Bryan 40 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 25 years' time?
|
Adam |
Bryan |
Total |
40 years ago |
3 u |
1 u |
4 u |
Change |
+ 40 |
+ 40 |
+ 80 |
Present |
3 u + 40 |
1 u + 40 |
100 |
(a)
Total age of Adam and Bryan 40 years ago
= 100 - 80
= 20
40 years ago
Adam's age = 3 u
Bryan's age = 1 u
Total age of Adam and Bryan = 4 u
4 u + 80 = 100
4 u = 100 - 80 = 20
1 u = 20 ÷ 4 = 5
Adam's age now
= 3 u + 40
= 3 x 5 + 40
= 15 + 40
= 55
(b)
Number of years that Adam is older than Bryan
= 3 u - 1 u
= 2 u
= 2 x 5
= 10
(c)
Bryan's age in 25 years' time
= 1 u + 40 + 25
= 5 + 40 + 25
= 70
Answer(s): (a) 55; (b) 10; (c) 70