Gabriel's auntie is 5 times as old as him. His auntie will be 42 years old in 12 years' time. In how many years' time will Gabriel's age be 70% that of his auntie's?
| |
Gabriel's auntie |
Gabriel |
Difference |
Before
(now) |
5x3 =
15 u |
1x3 =
3 u |
4x3 =
12 u |
| Change 1 |
+ 12 |
+ 12 |
|
| After 1 |
42 |
|
|
| Change 2 |
+ ? |
+ ? |
|
| After 2 |
10x4 =
40 u |
7x4 =
28 u |
3x4 =
12 u |
70% =
70100 =
710 Gabriel's auntie : Gabriel = 10 : 7
The difference in age between Gabriel's auntie and Gabriel always remains the same. Make the difference in age between Gabriel's auntie and Gabriel the same. LCM of 4 and 3 is 12.
15 u + 12 = 42
15 u = 42 - 12
15 u = 30
1 u = 30 ÷ 15 = 2
Number of years' time when Gabriel's age will be 70% that of his auntie's
= 40 u - 42
= 40 x 2 - 42
= 80 - 42
= 38
Answer(s): 38
