Sabrina was 9 years old last year. She was 24 years younger than Gillian.
- How old will her Gillian be 7 years later?
- In how many years' time will Sabrina's age be 13 of Gillian's age?
| |
Sabrina |
Gillian |
Difference |
| Before (Last year) |
9 |
33 |
24 |
| Change 1 |
+ 1 |
+ 1 |
|
| After 1 (Now) |
10 |
34 |
24 |
| Change 2 |
+ 7 |
+ 7 |
|
| After 2 (7 years later) |
|
? |
24 |
(a)
Gillian's age this year
= 9 + 24
= 33
Gillian's age this year
= 33 + 1
= 34
Gillian's age in 7 years' time
= 34 + 7
= 41
| |
Sabrina |
Gillian |
Difference |
| Before |
10 |
34 |
24 |
| Change |
+ ? |
+ ? |
|
| After |
1 u |
3 u |
2 u |
(b)
The difference in the age between Sabrina and Gillian at first and in the end remains unchanged.
Difference in the age between Sabrina and Gillian
= 3 u - 1 u
= 2 u
2 u = 24
1 u = 24 ÷ 2 = 12
Number of years' time that Sabrina's age be
13 of Gillian's age
= 12 - 10
= 2
Answer(s): (a) 41; (b) 2
