Xandra was 9 years old last year. She was 24 years younger than Erika.
- How old will her Erika be 5 years later?
- In how many years' time will Xandra's age be 13 of Erika's age?
| |
Xandra |
Erika |
Difference |
| Before (Last year) |
9 |
33 |
24 |
| Change 1 |
+ 1 |
+ 1 |
|
| After 1 (Now) |
10 |
34 |
24 |
| Change 2 |
+ 5 |
+ 5 |
|
| After 2 (5 years later) |
|
? |
24 |
(a)
Erika's age this year
= 9 + 24
= 33
Erika's age this year
= 33 + 1
= 34
Erika's age in 5 years' time
= 34 + 5
= 39
| |
Xandra |
Erika |
Difference |
| Before |
10 |
34 |
24 |
| Change |
+ ? |
+ ? |
|
| After |
1 u |
3 u |
2 u |
(b)
The difference in the age between Xandra and Erika at first and in the end remains unchanged.
Difference in the age between Xandra and Erika
= 3 u - 1 u
= 2 u
2 u = 24
1 u = 24 ÷ 2 = 12
Number of years' time that Xandra's age be
13 of Erika's age
= 12 - 10
= 2
Answer(s): (a) 39; (b) 2
