Adam is 10 years old. The total age of Adam and Bryan is 80 years. How many years' time will the ratio of Adam's age to Bryan's age be 1 : 3?
|
Adam |
Bryan |
Total |
Difference |
Before |
10 |
70 |
80 |
60 |
Change |
+ ? |
+ ? |
|
|
After |
1 u |
3 u |
|
2 u |
Bryan's age
= 80 - 10
= 70
Difference in the age between Adam and Bryan
= 70 - 10
= 60
Difference in the age between Adam and Bryan in units
= 3 u - 1 u
= 2 u
2 u = 60
1 u = 60 ÷ 2 = 30
Adam's age now = 10
Adam's age after = 1 u = 1 x 30 = 30
Number of years' time
= 30 - 10
= 20
Answer(s): 20