Dylan's age is
25 of his grandfather's. His grandfather will be 65 years old in 20 years' time. In how many years' time will Dylan's age be
710 that of his grandfather's?
| |
Dylan |
His grandfather |
Difference |
| Before |
2x1 =
2 u |
5x1 =
5 u |
3x1 =
3 u |
| Change 1 |
+ 20 |
+ 20 |
|
| After |
|
65 |
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
7x1 =
7 u |
10x1 =
10 u |
3x1 =
3 u |
The age difference between Dylan and his grandfather remains unchanged.
LCM of 3 and 3 is 3.
5 u + 20 = 65
5 u = 65 - 20
5 u = 45
1 u = 45 ÷ 5 = 9
Number of years' time when Dylan's age will be
710 that of his grandfather's age
= 7 u - 2 u
= 5 u
= 5 x 9
= 45
Answer(s): 45
