Marion was 7 years old last year. She was 26 years younger than Betty.
- How old will her Betty be 7 years later?
- In how many years' time will Marion's age be 13 of Betty's age?
|
Marion |
Betty |
Difference |
Before (Last year) |
7 |
33 |
26 |
Change 1 |
+ 1 |
+ 1 |
|
After 1 (Now) |
8 |
34 |
26 |
Change 2 |
+ 7 |
+ 7 |
|
After 2 (7 years later) |
|
? |
26 |
(a)
Betty's age this year
= 7 + 26
= 33
Betty's age this year
= 33 + 1
= 34
Betty's age in 7 years' time
= 34 + 7
= 41
|
Marion |
Betty |
Difference |
Before |
8 |
34 |
26 |
Change |
+ ? |
+ ? |
|
After |
1 u |
3 u |
2 u |
(b)
The difference in the age between Marion and Betty at first and in the end remains unchanged.
Difference in the age between Marion and Betty
= 3 u - 1 u
= 2 u
2 u = 26
1 u = 26 ÷ 2 = 13
Number of years' time that Marion's age be
13 of Betty's age
= 13 - 8
= 5
Answer(s): (a) 41; (b) 5