Gem will be 79 years old in 4 years' time. Now, Lucy's age is 45 of Gem's age. What was Lucy's age when she was 11 years less than 90% of Gem's age?
| |
Lucy |
Gem |
Difference |
| Before |
9 p - 11 |
10 p |
1 p + 11 |
| Change 1 |
+ ? |
+ ? |
|
| After 1 (Now) |
4 u |
5 u |
1 u |
| Change 2 |
+ 4 |
+ 4 |
|
| After |
4 u + 4 |
79 |
|
Gem's age in 4 years' time = 5 u + 4
5 u + 4 = 79
5 u = 79 - 4
5 u = 75
1 u = 75 ÷ 5 = 15
Difference between Gem's age and Lucy's age
= 1 u
= 15
90% =
90100 =
910 Difference in Gem's age and Lucy's age at first
= 10 p - (9 p - 11)
= 1 p + 11
The difference in age between Gem and Lucy remains unchanged.
1 p + 11 = 15
1 p = 15 - 11 = 4
Lucy's age when she was 11 years less than 90% of Gem's age
= 9 p - 11
= 9 x 4 - 11
= 36 - 11
= 25
Answer(s): 25
