David and Zane had $180 altogether. Zane gave
25 of his money to David. After that, David gave
35 of his money to Zane. In the end, David had
15 of the total sum of money. How much did David have at first?
| |
Zane |
David |
Total |
| Before 1 |
5 p |
? |
$180 |
| Change 1 |
- 2 p |
+ 2 p |
|
| After 1 |
3 p |
5 u |
|
| Before 2 |
3 p |
5x1 =
5 u |
$180 |
| Change 2 |
+ 3x1 =
+ 3 u |
- 3x1 =
- 3 u |
|
| After 2 |
|
2x1 =
2 u |
$180 |
Comparing between
Zane and David
in the end |
4x2 =
8 u |
1x2 =
2 u |
$180 |
The amount that David had in the end is the repeated. Make the amount that David had in the end the same. LCM of 2 and 1 is 2.
10 u = 180
1 u = 180 ÷ 10 = 18
5 u = 5 x 18 = 90
3 p = 180 - 90 = 90
1 p = 90 ÷ 3 = 30
Amount that Zane had at first
= 5 p
= 5 x 30
= $150
Amount that David had at first
= 180 - 150
= $30
Answer(s): $30
