Eric's mother is 3 times as old as him. His mother will be 37 years old in 7 years' time. In how many years' time will Eric's age be 75% that of his mother's?
| |
Eric's mother |
Eric |
Difference |
Before
(now) |
3x1 =
3 u |
1x1 =
1 u |
2x1 =
2 u |
| Change 1 |
+ 7 |
+ 7 |
|
| After 1 |
37 |
|
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
4x2 =
8 u |
3x2 =
6 u |
1x2 =
2 u |
75% =
75100 =
34 Eric's mother : Eric = 4 : 3
The difference in age between Eric's mother and Eric always remains the same. Make the difference in age between Eric's mother and Eric the same. LCM of 2 and 1 is 2.
3 u + 7 = 37
3 u = 37 - 7
3 u = 30
1 u = 30 ÷ 3 = 10
Number of years' time when Eric's age will be 75% that of his mother's
= 8 u - 37
= 8 x 10 - 37
= 80 - 37
= 43
Answer(s): 43
