Mark's auntie is 4 times as old as him. His auntie will be 35 years old in 11 years' time. In how many years' time will Mark's age be 75% that of his auntie's?
| |
Mark's auntie |
Mark |
Difference |
Before
(now) |
4x1 =
4 u |
1x1 =
1 u |
3x1 =
3 u |
| Change 1 |
+ 11 |
+ 11 |
|
| After 1 |
35 |
|
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
4x3 =
12 u |
3x3 =
9 u |
1x3 =
3 u |
75% =
75100 =
34 Mark's auntie : Mark = 4 : 3
The difference in age between Mark's auntie and Mark always remains the same. Make the difference in age between Mark's auntie and Mark the same. LCM of 3 and 1 is 3.
4 u + 11 = 35
4 u = 35 - 11
4 u = 24
1 u = 24 ÷ 4 = 6
Number of years' time when Mark's age will be 75% that of his auntie's
= 12 u - 35
= 12 x 6 - 35
= 72 - 35
= 37
Answer(s): 37
