Olivia had
49 as much money as Xuan. Olivia had $50 less than Xuan. Olivia spent some money to buy a birthday present for her best friend. In the end, she had
13 as much money as Xuan. How much did Olivia spend on the birthday present?
| |
Olivia |
Xuan |
| Before |
4 u |
9 u |
| Change |
- ? |
|
| After |
1 p |
3 p |
Amount that Olivia had less than Xuan
= 9 u - 4 u
= 5 u
5 u = 50
1 u = 50 ÷ 5 = 10
Amount that Olivia had at first
= 4 u
= 4 x 10
= $40
Amount that Xuan had
= 9 u
= 9 x 10
= $90
The amount that Xuan had at first and in the end remains the same.
9 u = 3 p
3 p = 90
1 p = 90 ÷ 3 = 30
Amount that Olivia had in the end
= 1 p
= $30
Amount that Olivia spent on the birthday present
= 40 - 30
= $10
Answer(s): $10
