Natalie had 1540 mℓ more milk than Cathy. After Natalie gave Cathy 420 mℓ of milk, the ratio of Natalie's milk to Cathy's milk became 5 : 3. How much milk did Natalie have at first? Give your answer in millilitres.
|
Natalie |
Cathy |
Difference |
Before |
1 u + 1540 |
1 u |
1540 |
Change |
- 420 |
+ 420 |
|
After |
1 u + 1120 |
1 u + 420 |
700 |
Comparing Natalie and Cathy in the end |
5 p |
3 p |
2 p |
Volume of milk that Natalie had in the end
= 1 u + 1540 - 420
= 1 u + 1120
Difference in the volume of milk between Natalie and Cathy in the end
= 5 p - 3 p
= 2 p
2 p = 1120 - 420
2 p = 700
1 p = 700 ÷ 2 = 350
Volume of milk that Natalie had at first
= 5 p + 420
= 5 x 350 + 420
= 1750 + 420
= 2170 mℓ
Answer(s): 2170 mℓ