Linda's auntie is 3 times as old as her. Linda will be 13 years old in 4 years' time. In how many years' time will Linda's age be 70% that of her auntie's?
|
Linda's auntie |
Linda |
Difference |
Before (now) |
3x3 = 9 u |
1x3 = 3 u |
2x3 = 6 u |
Change 1 |
+ 4 |
+ 4 |
|
After 1 |
|
13 |
|
Change 2 |
+ ? |
+ ? |
|
After 2 |
10x2 = 20 u |
7x2 = 14 u |
3x2 = 6 u |
70% =
70100 =
710 Linda's auntie : Linda = 10 : 7
The difference in age between Linda's auntie and Linda always remains the same. Make the difference in age between Linda's auntie and Linda the same. LCM of 2 and 3 is 6.
3 u + 4 = 13
3 u = 13 - 4
3 u = 9
1 u = 9 ÷ 3 = 3
Number of years' time when Linda's age will be 70% that of her auntie's
= 20 u - 31
= 20 x 3 - 31
= 60 - 31
= 29
Answer(s): 29