Elyse had 1890 mℓ more milk than Opal. After Elyse gave Opal 540 mℓ of milk, the ratio of Elyse's milk to Opal's milk became 7 : 4. How much milk did Elyse have at first? Give your answer in millilitres.
| |
Elyse |
Opal |
Difference |
| Before |
1 u + 1890 |
1 u |
1890 |
| Change |
- 540 |
+ 540 |
|
| After |
1 u + 1350 |
1 u + 540 |
810 |
Comparing Elyse and
Opal in the end |
7 p |
4 p |
3 p |
Volume of milk that Elyse had in the end
= 1 u + 1890 - 540
= 1 u + 1350
Difference in the volume of milk between Elyse and Opal in the end
= 7 p - 4 p
= 3 p
3 p = 1350 - 540
3 p = 810
1 p = 810 ÷ 3 = 270
Volume of milk that Elyse had at first
= 7 p + 540
= 7 x 270 + 540
= 1890 + 540
= 2430 mℓ
Answer(s): 2430 mℓ
