Diana and Billy had a total of $105. After Diana spent
13 of her money and Billy spent $15, the ratio of Diana's money to Kennenth's money became 1 : 6. How much money had Billy at first?
| |
Diana |
Billy |
Total |
| Before |
3 u |
12 u + $15 |
$105 |
| Change |
- 1 u |
- $15 |
|
| After |
2 u |
|
|
Comparing Diana and
Billy in the end |
1x2 =
2 u |
6x2 =
12 u |
|
The amount that Diana had in the end is repeated. Make the amount that Diana had in the end the same. LCM of 2 and 1 is 2.
Total amount that Diana and Billy had at first
= 3 u + 12 u + 15
= 15 u + 15
15 u + 15 = 105
15 u = 105 - 15
15 u = 90
1 u = 90 ÷ 15 = 6
Amount that Billy had at first
= 12 u + 15
= 12 x 6 + 15
= 72 + 15
= $87
Answer(s): $87
