Adam was 4 times as old as Bryan 20 years ago.
Their total present age is 90 years now.
- How old is Adam now?
- How many years is Adam older than Bryan?
- How old is Bryan in 5 years' time?
|
Adam |
Bryan |
Total |
20 years ago |
4 u |
1 u |
5 u |
Change |
+ 20 |
+ 20 |
+ 40 |
Present |
4 u + 20 |
1 u + 20 |
90 |
(a)
Total age of Adam and Bryan 20 years ago
= 90 - 40
= 50
20 years ago
Adam's age = 4 u
Bryan's age = 1 u
Total age of Adam and Bryan = 5 u
5 u + 40 = 90
5 u = 90 - 40 = 50
1 u = 50 ÷ 5 = 10
Adam's age now
= 4 u + 20
= 4 x 10 + 20
= 40 + 20
= 60
(b)
Number of years that Adam is older than Bryan
= 4 u - 1 u
= 3 u
= 3 x 10
= 30
(c)
Bryan's age in 5 years' time
= 1 u + 20 + 5
= 10 + 20 + 5
= 35
Answer(s): (a) 60; (b) 30; (c) 35