Opal had 1390 mℓ more orange juice than Sabrina. After Opal gave Sabrina 410 mℓ of orange juice, the ratio of Opal's orange juice to Sabrina's orange juice became 7 : 4. How much orange juice did Opal have at first? Give your answer in millilitres.
| |
Opal |
Sabrina |
Difference |
| Before |
1 u + 1390 |
1 u |
1390 |
| Change |
- 410 |
+ 410 |
|
| After |
1 u + 980 |
1 u + 410 |
570 |
Comparing Opal and
Sabrina in the end |
7 p |
4 p |
3 p |
Volume of orange juice that Opal had in the end
= 1 u + 1390 - 410
= 1 u + 980
Difference in the volume of orange juice between Opal and Sabrina in the end
= 7 p - 4 p
= 3 p
3 p = 980 - 410
3 p = 570
1 p = 570 ÷ 3 = 190
Volume of orange juice that Opal had at first
= 7 p + 410
= 7 x 190 + 410
= 1330 + 410
= 1740 mℓ
Answer(s): 1740 mℓ
