The ratio of the amount of money that Lucy and Kathy brought along was 3 : 4. For their sister's gift, Lucy and Kathy shared the cost in the ratio of 2 : 3. Lucy used up
25 of her money to pay for her share. After paying for her share, Kathy had $231 left. How much was the gift?
|
Lucy |
Kathy |
Before |
3 u |
4 u |
Change |
- 1.2 u |
- 1.8 u |
Comparing the cost shared between Lucy and Kathy |
- 2 p = - 1.2 u |
- 3 p = - 1.8 u |
After |
1.8 u |
231 |
Amount that Lucy spent on the gift
=
25 x 3 u
= 1.2 u
2 p = 1.2 u
1 p = 1.2 u ÷ 2 = 0.6
3 p = 3 x 0.6 = 1.8 u
Amount that Kathy had left
= 4 u - 1.8 u
= 2.2 u
2.2 u = 231
1 u = 231 ÷ 2.2 = 105
Cost of the gift
= 1.2 u + 1.8 u
= 3 u
= 3 x 105
= $315
Answer: $315