Adam is 10 years old. The total age of Adam and Bryan is 60 years. How many years' time will the ratio of Adam's age to Bryan's age be 3 : 7?
|
Adam |
Bryan |
Total |
Difference |
Before |
10 |
50 |
60 |
40 |
Change |
+ ? |
+ ? |
|
|
After |
3 u |
7 u |
|
4 u |
Bryan's age
= 60 - 10
= 50
Difference in the age between Adam and Bryan
= 50 - 10
= 40
Difference in the age between Adam and Bryan in units
= 7 u - 3 u
= 4 u
4 u = 40
1 u = 40 ÷ 4 = 10
Adam's age now = 10
Adam's age after = 3 u = 3 x 10 = 30
Number of years' time
= 30 - 10
= 20
Answer(s): 20