Hilda was 9 years old last year. She was 28 years younger than Dana.
- How old will her Dana be 7 years later?
- In how many years' time will Hilda's age be 13 of Dana's age?
| |
Hilda |
Dana |
Difference |
| Before (Last year) |
9 |
37 |
28 |
| Change 1 |
+ 1 |
+ 1 |
|
| After 1 (Now) |
10 |
38 |
28 |
| Change 2 |
+ 7 |
+ 7 |
|
| After 2 (7 years later) |
|
? |
28 |
(a)
Dana's age this year
= 9 + 28
= 37
Dana's age this year
= 37 + 1
= 38
Dana's age in 7 years' time
= 38 + 7
= 45
| |
Hilda |
Dana |
Difference |
| Before |
10 |
38 |
28 |
| Change |
+ ? |
+ ? |
|
| After |
1 u |
3 u |
2 u |
(b)
The difference in the age between Hilda and Dana at first and in the end remains unchanged.
Difference in the age between Hilda and Dana
= 3 u - 1 u
= 2 u
2 u = 28
1 u = 28 ÷ 2 = 14
Number of years' time that Hilda's age be
13 of Dana's age
= 14 - 10
= 4
Answer(s): (a) 45; (b) 4
