Last year, Pierre was 5 times as old as his son, Zane. This year, their total age is 56 years old. How old will Pierre be when he is 3 times as old as Zane?
| |
Pierre |
Zane |
Difference |
Total |
| Before |
5x1 =
5 u |
1x1 =
1 u |
4x1 =
4 u |
|
| Change 1 |
+ 1 |
+ 1 |
|
|
| After 1 |
5 u + 1 |
1 u + 1 |
|
56 |
| 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 Pierre and his son this year
= 5 u + 1 + 1 u + 1
= 6 u + 2
6 u + 2 = 56
6 u = 56 - 2
6 u = 54
1 u = 54 ÷ 6 = 9
Pierre's age when he is 3 times as old as Zane
= 6 u
= 6 x 9
= 54
Answer(s): 54
