Mary and Pierre had a total of $142. After Mary spent
57 of her money and Pierre spent $12, the ratio of Mary's money to Kennenth's money became 1 : 3. How much money had Pierre at first?
| |
Mary |
Pierre |
Total |
| Before |
7 u |
6 u + $12 |
$142 |
| Change |
- 5 u |
- $12 |
|
| After |
2 u |
|
|
Comparing Mary and
Pierre in the end |
1x2 =
2 u |
3x2 =
6 u |
|
The amount that Mary had in the end is repeated. Make the amount that Mary had in the end the same. LCM of 2 and 1 is 2.
Total amount that Mary and Pierre had at first
= 7 u + 6 u + 12
= 13 u + 12
13 u + 12 = 142
13 u = 142 - 12
13 u = 130
1 u = 130 ÷ 13 = 10
Amount that Pierre had at first
= 6 u + 12
= 6 x 10 + 12
= 60 + 12
= $72
Answer(s): $72
