Cathy had 1830 mℓ more soy milk than Ivory. After Cathy gave Ivory 480 mℓ of soy milk, the ratio of Cathy's soy milk to Ivory's soy milk became 5 : 2. How much soy milk did Cathy have at first? Give your answer in millilitres.
|
Cathy |
Ivory |
Difference |
Before |
1 u + 1830 |
1 u |
1830 |
Change |
- 480 |
+ 480 |
|
After |
1 u + 1350 |
1 u + 480 |
870 |
Comparing Cathy and Ivory in the end |
5 p |
2 p |
3 p |
Volume of soy milk that Cathy had in the end
= 1 u + 1830 - 480
= 1 u + 1350
Difference in the volume of soy milk between Cathy and Ivory in the end
= 5 p - 2 p
= 3 p
3 p = 1350 - 480
3 p = 870
1 p = 870 ÷ 3 = 290
Volume of soy milk that Cathy had at first
= 5 p + 480
= 5 x 290 + 480
= 1450 + 480
= 1930 mℓ
Answer(s): 1930 mℓ