Risa and Sarah had equal amount of money. Each day, Risa spent $12 and Sarah spent $19. When Risa had $105 left, Sarah had
15 as much money left as Risa. How much money did the two girls have at first?
| |
Risa |
Sarah |
| Before |
12 u + 105 |
19 u + 21 |
| Change |
- 12 u |
- 19 u |
| After |
$105 |
$21 |
Amount that Sarah had left
=
15 x 105
= $21
The amount that Risa and Sarah had at first is the same.
19 u + 21 = 12 u + 105
19 u - 12 u = 105 - 21
7 u = 84
1 u = 84 ÷ 7 = 12
Amount that Risa had at first
= 12 u + 105
= 12 x 12 + 105
= 144 + 105
= $249
Total amount that both girls had at first
= 2 x 249
= $498
Answer(s): $498
