Winnie had 1640 mℓ more coffee than Gem. After Winnie gave Gem 500 mℓ of coffee, the ratio of Winnie's coffee to Gem's coffee became 5 : 3. How much coffee did Winnie have at first? Give your answer in millilitres.
| |
Winnie |
Gem |
Difference |
| Before |
1 u + 1640 |
1 u |
1640 |
| Change |
- 500 |
+ 500 |
|
| After |
1 u + 1140 |
1 u + 500 |
640 |
Comparing Winnie and
Gem in the end |
5 p |
3 p |
2 p |
Volume of coffee that Winnie had in the end
= 1 u + 1640 - 500
= 1 u + 1140
Difference in the volume of coffee between Winnie and Gem in the end
= 5 p - 3 p
= 2 p
2 p = 1140 - 500
2 p = 640
1 p = 640 ÷ 2 = 320
Volume of coffee that Winnie had at first
= 5 p + 500
= 5 x 320 + 500
= 1600 + 500
= 2100 mℓ
Answer(s): 2100 mℓ
