Sarah was 6 years old last year. She was 28 years younger than Gem.
- How old will her Gem be 5 years later?
- In how many years' time will Sarah's age be 13 of Gem's age?
| |
Sarah |
Gem |
Difference |
| Before (Last year) |
6 |
34 |
28 |
| Change 1 |
+ 1 |
+ 1 |
|
| After 1 (Now) |
7 |
35 |
28 |
| Change 2 |
+ 5 |
+ 5 |
|
| After 2 (5 years later) |
|
? |
28 |
(a)
Gem's age this year
= 6 + 28
= 34
Gem's age this year
= 34 + 1
= 35
Gem's age in 5 years' time
= 35 + 5
= 40
| |
Sarah |
Gem |
Difference |
| Before |
7 |
35 |
28 |
| Change |
+ ? |
+ ? |
|
| After |
1 u |
3 u |
2 u |
(b)
The difference in the age between Sarah and Gem at first and in the end remains unchanged.
Difference in the age between Sarah and Gem
= 3 u - 1 u
= 2 u
2 u = 28
1 u = 28 ÷ 2 = 14
Number of years' time that Sarah's age be
13 of Gem's age
= 14 - 7
= 7
Answer(s): (a) 40; (b) 7
