Adam was 4 times as old as Bryan 40 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 15 years' time?
|
Adam |
Bryan |
Total |
40 years ago |
4 u |
1 u |
5 u |
Change |
+ 40 |
+ 40 |
+ 80 |
Present |
4 u + 40 |
1 u + 40 |
90 |
(a)
Total age of Adam and Bryan 40 years ago
= 90 - 80
= 10
40 years ago
Adam's age = 4 u
Bryan's age = 1 u
Total age of Adam and Bryan = 5 u
5 u + 80 = 90
5 u = 90 - 80 = 10
1 u = 10 ÷ 5 = 2
Adam's age now
= 4 u + 40
= 4 x 2 + 40
= 8 + 40
= 48
(b)
Number of years that Adam is older than Bryan
= 4 u - 1 u
= 3 u
= 3 x 2
= 6
(c)
Bryan's age in 15 years' time
= 1 u + 40 + 15
= 2 + 40 + 15
= 57
Answer(s): (a) 48; (b) 6; (c) 57