Mary and Tom had a total of $83. After Mary spent
57 of her money and Tom spent $18, the ratio of Mary's money to Kennenth's money became 1 : 3. How much money had Tom at first?
| |
Mary |
Tom |
Total |
| Before |
7 u |
6 u + $18 |
$83 |
| Change |
- 5 u |
- $18 |
|
| After |
2 u |
|
|
Comparing Mary and
Tom 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 Tom had at first
= 7 u + 6 u + 18
= 13 u + 18
13 u + 18 = 83
13 u = 83 - 18
13 u = 65
1 u = 65 ÷ 13 = 5
Amount that Tom had at first
= 6 u + 18
= 6 x 5 + 18
= 30 + 18
= $48
Answer(s): $48
