Bryan's father is 7 times as old as him. His father will be 32 years old in 4 years' time. In how many years' time will Bryan's age be 70% that of his father's?
| |
Bryan's father |
Bryan |
Difference |
Before
(now) |
7x1 =
7 u |
1x1 =
1 u |
6x1 =
6 u |
| Change 1 |
+ 4 |
+ 4 |
|
| After 1 |
32 |
|
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
10x2 =
20 u |
7x2 =
14 u |
3x2 =
6 u |
70% =
70100 =
710 Bryan's father : Bryan = 10 : 7
The difference in age between Bryan's father and Bryan always remains the same. Make the difference in age between Bryan's father and Bryan the same. LCM of 6 and 3 is 6.
7 u + 4 = 32
7 u = 32 - 4
7 u = 28
1 u = 28 ÷ 7 = 4
Number of years' time when Bryan's age will be 70% that of his father's
= 20 u - 32
= 20 x 4 - 32
= 80 - 32
= 48
Answer(s): 48
