Adam was 4 times as old as Bryan 20 years ago.
Their total present age is 70 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 |
20 years ago |
4 u |
1 u |
5 u |
Change |
+ 20 |
+ 20 |
+ 40 |
Present |
4 u + 20 |
1 u + 20 |
70 |
(a)
Total age of Adam and Bryan 20 years ago
= 70 - 40
= 30
20 years ago
Adam's age = 4 u
Bryan's age = 1 u
Total age of Adam and Bryan = 5 u
5 u + 40 = 70
5 u = 70 - 40 = 30
1 u = 30 ÷ 5 = 6
Adam's age now
= 4 u + 20
= 4 x 6 + 20
= 24 + 20
= 44
(b)
Number of years that Adam is older than Bryan
= 4 u - 1 u
= 3 u
= 3 x 6
= 18
(c)
Bryan's age in 10 years' time
= 1 u + 20 + 10
= 6 + 20 + 10
= 36
Answer(s): (a) 44; (b) 18; (c) 36