Nora had 1600 mℓ more coffee than Abi. After Nora gave Abi 530 mℓ of coffee, the ratio of Nora's coffee to Abi's coffee became 7 : 4. How much coffee did Nora have at first? Give your answer in millilitres.
| |
Nora |
Abi |
Difference |
| Before |
1 u + 1600 |
1 u |
1600 |
| Change |
- 530 |
+ 530 |
|
| After |
1 u + 1070 |
1 u + 530 |
540 |
Comparing Nora and
Abi in the end |
7 p |
4 p |
3 p |
Volume of coffee that Nora had in the end
= 1 u + 1600 - 530
= 1 u + 1070
Difference in the volume of coffee between Nora and Abi in the end
= 7 p - 4 p
= 3 p
3 p = 1070 - 530
3 p = 540
1 p = 540 ÷ 3 = 180
Volume of coffee that Nora had at first
= 7 p + 530
= 7 x 180 + 530
= 1260 + 530
= 1790 mℓ
Answer(s): 1790 mℓ
