Cathy was 8 years old last year. She was 26 years younger than Dana.
- How old will her Dana be 7 years later?
- In how many years' time will Cathy's age be 13 of Dana's age?
| |
Cathy |
Dana |
Difference |
| Before (Last year) |
8 |
34 |
26 |
| Change 1 |
+ 1 |
+ 1 |
|
| After 1 (Now) |
9 |
35 |
26 |
| Change 2 |
+ 7 |
+ 7 |
|
| After 2 (7 years later) |
|
? |
26 |
(a)
Dana's age this year
= 8 + 26
= 34
Dana's age this year
= 34 + 1
= 35
Dana's age in 7 years' time
= 35 + 7
= 42
| |
Cathy |
Dana |
Difference |
| Before |
9 |
35 |
26 |
| Change |
+ ? |
+ ? |
|
| After |
1 u |
3 u |
2 u |
(b)
The difference in the age between Cathy and Dana at first and in the end remains unchanged.
Difference in the age between Cathy and Dana
= 3 u - 1 u
= 2 u
2 u = 26
1 u = 26 ÷ 2 = 13
Number of years' time that Cathy's age be
13 of Dana's age
= 13 - 9
= 4
Answer(s): (a) 42; (b) 4
