Tina had 1740 mℓ more soy milk than Kathy. After Tina gave Kathy 510 mℓ of soy milk, the ratio of Tina's soy milk to Kathy's soy milk became 7 : 3. How much soy milk did Tina have at first? Give your answer in millilitres.
|
Tina |
Kathy |
Difference |
Before |
1 u + 1740 |
1 u |
1740 |
Change |
- 510 |
+ 510 |
|
After |
1 u + 1230 |
1 u + 510 |
720 |
Comparing Tina and Kathy in the end |
7 p |
3 p |
4 p |
Volume of soy milk that Tina had in the end
= 1 u + 1740 - 510
= 1 u + 1230
Difference in the volume of soy milk between Tina and Kathy in the end
= 7 p - 3 p
= 4 p
4 p = 1230 - 510
4 p = 720
1 p = 720 ÷ 4 = 180
Volume of soy milk that Tina had at first
= 7 p + 510
= 7 x 180 + 510
= 1260 + 510
= 1770 mℓ
Answer(s): 1770 mℓ