Barbara was 7 years old last year. She was 28 years younger than Betty.
- How old will her Betty be 8 years later?
- In how many years' time will Barbara's age be 13 of Betty's age?
| |
Barbara |
Betty |
Difference |
| Before (Last year) |
7 |
35 |
28 |
| Change 1 |
+ 1 |
+ 1 |
|
| After 1 (Now) |
8 |
36 |
28 |
| Change 2 |
+ 8 |
+ 8 |
|
| After 2 (8 years later) |
|
? |
28 |
(a)
Betty's age this year
= 7 + 28
= 35
Betty's age this year
= 35 + 1
= 36
Betty's age in 8 years' time
= 36 + 8
= 44
| |
Barbara |
Betty |
Difference |
| Before |
8 |
36 |
28 |
| Change |
+ ? |
+ ? |
|
| After |
1 u |
3 u |
2 u |
(b)
The difference in the age between Barbara and Betty at first and in the end remains unchanged.
Difference in the age between Barbara and Betty
= 3 u - 1 u
= 2 u
2 u = 28
1 u = 28 ÷ 2 = 14
Number of years' time that Barbara's age be
13 of Betty's age
= 14 - 8
= 6
Answer(s): (a) 44; (b) 6
