Adam was 4 times as old as Bryan 10 years ago.
Their total present age is 40 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 |
10 years ago |
4 u |
1 u |
5 u |
Change |
+ 10 |
+ 10 |
+ 20 |
Present |
4 u + 10 |
1 u + 10 |
40 |
(a)
Total age of Adam and Bryan 10 years ago
= 40 - 20
= 20
10 years ago
Adam's age = 4 u
Bryan's age = 1 u
Total age of Adam and Bryan = 5 u
5 u + 20 = 40
5 u = 40 - 20 = 20
1 u = 20 ÷ 5 = 4
Adam's age now
= 4 u + 10
= 4 x 4 + 10
= 16 + 10
= 26
(b)
Number of years that Adam is older than Bryan
= 4 u - 1 u
= 3 u
= 3 x 4
= 12
(c)
Bryan's age in 25 years' time
= 1 u + 10 + 25
= 4 + 10 + 25
= 39
Answer(s): (a) 26; (b) 12; (c) 39