Adam was 4 times as old as Bryan 10 years ago.
Their total present age is 80 years now.
- How old is Adam now?
- How many years is Adam older than Bryan?
- How old is Bryan in 30 years' time?
|
Adam |
Bryan |
Total |
10 years ago |
4 u |
1 u |
5 u |
Change |
+ 10 |
+ 10 |
+ 20 |
Present |
4 u + 10 |
1 u + 10 |
80 |
(a)
Total age of Adam and Bryan 10 years ago
= 80 - 20
= 60
10 years ago
Adam's age = 4 u
Bryan's age = 1 u
Total age of Adam and Bryan = 5 u
5 u + 20 = 80
5 u = 80 - 20 = 60
1 u = 60 ÷ 5 = 12
Adam's age now
= 4 u + 10
= 4 x 12 + 10
= 48 + 10
= 58
(b)
Number of years that Adam is older than Bryan
= 4 u - 1 u
= 3 u
= 3 x 12
= 36
(c)
Bryan's age in 30 years' time
= 1 u + 10 + 30
= 12 + 10 + 30
= 52
Answer(s): (a) 58; (b) 36; (c) 52