Yen was 6 years old last year. She was 22 years younger than Shiyun.
- How old will her Shiyun be 7 years later?
- In how many years' time will Yen's age be 13 of Shiyun's age?
| |
Yen |
Shiyun |
Difference |
| Before (Last year) |
6 |
28 |
22 |
| Change 1 |
+ 1 |
+ 1 |
|
| After 1 (Now) |
7 |
29 |
22 |
| Change 2 |
+ 7 |
+ 7 |
|
| After 2 (7 years later) |
|
? |
22 |
(a)
Shiyun's age this year
= 6 + 22
= 28
Shiyun's age this year
= 28 + 1
= 29
Shiyun's age in 7 years' time
= 29 + 7
= 36
| |
Yen |
Shiyun |
Difference |
| Before |
7 |
29 |
22 |
| Change |
+ ? |
+ ? |
|
| After |
1 u |
3 u |
2 u |
(b)
The difference in the age between Yen and Shiyun at first and in the end remains unchanged.
Difference in the age between Yen and Shiyun
= 3 u - 1 u
= 2 u
2 u = 22
1 u = 22 ÷ 2 = 11
Number of years' time that Yen's age be
13 of Shiyun's age
= 11 - 7
= 4
Answer(s): (a) 36; (b) 4
