Adam was 4 times as old as Bryan 15 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 25 years' time?
|
Adam |
Bryan |
Total |
15 years ago |
4 u |
1 u |
5 u |
Change |
+ 15 |
+ 15 |
+ 30 |
Present |
4 u + 15 |
1 u + 15 |
90 |
(a)
Total age of Adam and Bryan 15 years ago
= 90 - 30
= 60
15 years ago
Adam's age = 4 u
Bryan's age = 1 u
Total age of Adam and Bryan = 5 u
5 u + 30 = 90
5 u = 90 - 30 = 60
1 u = 60 ÷ 5 = 12
Adam's age now
= 4 u + 15
= 4 x 12 + 15
= 48 + 15
= 63
(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 25 years' time
= 1 u + 15 + 25
= 12 + 15 + 25
= 52
Answer(s): (a) 63; (b) 36; (c) 52