Xuan had $480 less than David. David spent 0.7 of his money and Xuan spent 0.3 of her money. In the end, David and Xuan had the same amount of money left. Find the amount of money Xuan had at first.
| |
Xuan |
David |
Difference |
| Before |
30 u |
70 u |
40 u |
| Change |
- 3 u |
- 7 u |
|
| After |
21 u |
21 u |
|
0.7 =
710 Fraction of David's amount left
= 1 -
710 =
310 0.3 =
310 Fraction of Xuan's amount left
= 1 -
310 =
710 The amount that David and Xuan each had in the end is the same. Make the numerators the same. LCM of 3 and 7 is 21.
310 of David's amount =
710 of Xuan's amount
2170 of David's amount =
2130 of Xuan's amount
Amount that Xuan had less than David
= 70 u - 30 u
= 40 u
40 u = 480
1 u = 480 ÷ 40 = 12
Amount that Xuan had at first
= 30 u
= 30 x 12
= $360
Answer(s): $360
