Tina will be 24 years old in 4 years' time. Now, Gem's age is 12 of Tina's age. What was Gem's age when she was 5 years less than 90% of Tina's age?
| |
Gem |
Tina |
Difference |
| Before |
9 p - 5 |
10 p |
1 p + 5 |
| Change 1 |
+ ? |
+ ? |
|
| After 1 (Now) |
1 u |
2 u |
1 u |
| Change 2 |
+ 4 |
+ 4 |
|
| After |
1 u + 4 |
24 |
|
Tina's age in 4 years' time = 2 u + 4
2 u + 4 = 24
2 u = 24 - 4
2 u = 20
1 u = 20 ÷ 2 = 10
Difference between Tina's age and Gem's age
= 1 u
= 10
90% =
90100 =
910 Difference in Tina's age and Gem's age at first
= 10 p - (9 p - 5)
= 1 p + 5
The difference in age between Tina and Gem remains unchanged.
1 p + 5 = 10
1 p = 10 - 5 = 5
Gem's age when she was 5 years less than 90% of Tina's age
= 9 p - 5
= 9 x 5 - 5
= 45 - 5
= 40
Answer(s): 40
