Last year, Tom was 5 times as old as his son, Justin. This year, their total age is 50 years old. How old will Justin be when Tom is 3 times as old as him?
| |
Tom |
Justin |
Difference |
Total |
| Before |
5x1 =
5 u |
1x1 =
1 u |
4x1 =
4 u |
|
| Change 1 |
+ 1 |
+ 1 |
|
|
| After 1 |
5 u + 1 |
1 u + 1 |
|
50 |
| Change |
+ ? |
+ ? |
|
|
After 2 |
3x2 =
6 u |
1x2 =
2 u |
2x2 =
4 u |
|
The difference in Ben's age and his son's age always remains unchanged. Make the difference in age the same. LCM of 4 and 2 is 4.
Total age of Tom and his son this year
= 5 u + 1 + 1 u + 1
= 6 u + 2
6 u + 2 = 50
6 u = 50 - 2
6 u = 48
1 u = 48 ÷ 6 = 8
Tom's age when Tom is 3 times as old as him
= 2 u
= 2 x 8
= 16
Answer(s): 16
