Gillian had 1520 mℓ more coffee than Penelope. After Gillian gave Penelope 470 mℓ of coffee, the ratio of Gillian's coffee to Penelope's coffee became 5 : 3. How much coffee did Gillian have at first? Give your answer in millilitres.
| |
Gillian |
Penelope |
Difference |
| Before |
1 u + 1520 |
1 u |
1520 |
| Change |
- 470 |
+ 470 |
|
| After |
1 u + 1050 |
1 u + 470 |
580 |
Comparing Gillian and
Penelope in the end |
5 p |
3 p |
2 p |
Volume of coffee that Gillian had in the end
= 1 u + 1520 - 470
= 1 u + 1050
Difference in the volume of coffee between Gillian and Penelope in the end
= 5 p - 3 p
= 2 p
2 p = 1050 - 470
2 p = 580
1 p = 580 ÷ 2 = 290
Volume of coffee that Gillian had at first
= 5 p + 470
= 5 x 290 + 470
= 1450 + 470
= 1920 mℓ
Answer(s): 1920 mℓ
