Anna had 1980 mℓ more milk than Nora. After Anna gave Nora 510 mℓ of milk, the ratio of Anna's milk to Nora's milk became 7 : 3. How much milk did Anna have at first? Give your answer in millilitres.
|
Anna |
Nora |
Difference |
Before |
1 u + 1980 |
1 u |
1980 |
Change |
- 510 |
+ 510 |
|
After |
1 u + 1470 |
1 u + 510 |
960 |
Comparing Anna and Nora in the end |
7 p |
3 p |
4 p |
Volume of milk that Anna had in the end
= 1 u + 1980 - 510
= 1 u + 1470
Difference in the volume of milk between Anna and Nora in the end
= 7 p - 3 p
= 4 p
4 p = 1470 - 510
4 p = 960
1 p = 960 ÷ 4 = 240
Volume of milk that Anna had at first
= 7 p + 510
= 7 x 240 + 510
= 1680 + 510
= 2190 mℓ
Answer(s): 2190 mℓ