Adam was 4 times as old as Bryan 15 years ago.
Their total present age is 50 years now.
- How old is Adam now?
- How many years is Adam older than Bryan?
- How old is Bryan in 20 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 |
50 |
(a)
Total age of Adam and Bryan 15 years ago
= 50 - 30
= 20
15 years ago
Adam's age = 4 u
Bryan's age = 1 u
Total age of Adam and Bryan = 5 u
5 u + 30 = 50
5 u = 50 - 30 = 20
1 u = 20 ÷ 5 = 4
Adam's age now
= 4 u + 15
= 4 x 4 + 15
= 16 + 15
= 31
(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 20 years' time
= 1 u + 15 + 20
= 4 + 15 + 20
= 39
Answer(s): (a) 31; (b) 12; (c) 39