Eva was 7 years old last year. She was 28 years younger than Erika.
- How old will her Erika be 3 years later?
- In how many years' time will Eva's age be 13 of Erika's age?
| |
Eva |
Erika |
Difference |
| Before (Last year) |
7 |
35 |
28 |
| Change 1 |
+ 1 |
+ 1 |
|
| After 1 (Now) |
8 |
36 |
28 |
| Change 2 |
+ 3 |
+ 3 |
|
| After 2 (3 years later) |
|
? |
28 |
(a)
Erika's age this year
= 7 + 28
= 35
Erika's age this year
= 35 + 1
= 36
Erika's age in 3 years' time
= 36 + 3
= 39
| |
Eva |
Erika |
Difference |
| Before |
8 |
36 |
28 |
| Change |
+ ? |
+ ? |
|
| After |
1 u |
3 u |
2 u |
(b)
The difference in the age between Eva and Erika at first and in the end remains unchanged.
Difference in the age between Eva and Erika
= 3 u - 1 u
= 2 u
2 u = 28
1 u = 28 ÷ 2 = 14
Number of years' time that Eva's age be
13 of Erika's age
= 14 - 8
= 6
Answer(s): (a) 39; (b) 6
