Betty had 1810 mℓ more soy milk than Hazel. After Betty gave Hazel 410 mℓ of soy milk, the ratio of Betty's soy milk to Hazel's soy milk became 7 : 4. How much soy milk did Betty have at first? Give your answer in millilitres.
|
Betty |
Hazel |
Difference |
Before |
1 u + 1810 |
1 u |
1810 |
Change |
- 410 |
+ 410 |
|
After |
1 u + 1400 |
1 u + 410 |
990 |
Comparing Betty and Hazel in the end |
7 p |
4 p |
3 p |
Volume of soy milk that Betty had in the end
= 1 u + 1810 - 410
= 1 u + 1400
Difference in the volume of soy milk between Betty and Hazel in the end
= 7 p - 4 p
= 3 p
3 p = 1400 - 410
3 p = 990
1 p = 990 ÷ 3 = 330
Volume of soy milk that Betty had at first
= 7 p + 410
= 7 x 330 + 410
= 2310 + 410
= 2720 mℓ
Answer(s): 2720 mℓ