Adam was 3 times as old as Bryan 5 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 10 years' time?
|
Adam |
Bryan |
Total |
5 years ago |
3 u |
1 u |
4 u |
Change |
+ 5 |
+ 5 |
+ 10 |
Present |
3 u + 5 |
1 u + 5 |
90 |
(a)
Total age of Adam and Bryan 5 years ago
= 90 - 10
= 80
5 years ago
Adam's age = 3 u
Bryan's age = 1 u
Total age of Adam and Bryan = 4 u
4 u + 10 = 90
4 u = 90 - 10 = 80
1 u = 80 ÷ 4 = 20
Adam's age now
= 3 u + 5
= 3 x 20 + 5
= 60 + 5
= 65
(b)
Number of years that Adam is older than Bryan
= 3 u - 1 u
= 2 u
= 2 x 20
= 40
(c)
Bryan's age in 10 years' time
= 1 u + 5 + 10
= 20 + 5 + 10
= 35
Answer(s): (a) 65; (b) 40; (c) 35