Bryan is 10 years old. The total age of Bryan and Adam is 80 years. How many years' time will the ratio of Bryan's age to Adam's age be 1 : 4?
|
Bryan |
Adam |
Total |
Difference |
Before |
10 |
70 |
80 |
60 |
Change |
+ ? |
+ ? |
|
|
After |
1 u |
4 u |
|
3 u |
Adam's age
= 80 - 10
= 70
Difference in the age between Bryan and Adam
= 70 - 10
= 60
Difference in the age between Bryan and Adam in units
= 4 u - 1 u
= 3 u
3 u = 60
1 u = 60 ÷ 3 = 20
Bryan's age now = 10
Bryan's age after = 1 u = 1 x 20 = 20
Number of years' time
= 20 - 10
= 10
Answer(s): 10