Linda and Billy had a total of $72. After Linda spent
37 of her money and Billy spent $15, the ratio of Linda's money to Kennenth's money became 1 : 3. How much money had Billy at first?
| |
Linda |
Billy |
Total |
| Before |
7 u |
12 u + $15 |
$72 |
| Change |
- 3 u |
- $15 |
|
| After |
4 u |
|
|
Comparing Linda and
Billy in the end |
1x4 =
4 u |
3x4 =
12 u |
|
The amount that Linda had in the end is repeated. Make the amount that Linda had in the end the same. LCM of 4 and 1 is 4.
Total amount that Linda and Billy had at first
= 7 u + 12 u + 15
= 19 u + 15
19 u + 15 = 72
19 u = 72 - 15
19 u = 57
1 u = 57 ÷ 19 = 3
Amount that Billy had at first
= 12 u + 15
= 12 x 3 + 15
= 36 + 15
= $51
Answer(s): $51
