Gabby had 1500 mℓ more coffee than Lynn. After Gabby gave Lynn 510 mℓ of coffee, the ratio of Gabby's coffee to Lynn's coffee became 7 : 4. How much coffee did Gabby have at first? Give your answer in millilitres.
| |
Gabby |
Lynn |
Difference |
| Before |
1 u + 1500 |
1 u |
1500 |
| Change |
- 510 |
+ 510 |
|
| After |
1 u + 990 |
1 u + 510 |
480 |
Comparing Gabby and
Lynn in the end |
7 p |
4 p |
3 p |
Volume of coffee that Gabby had in the end
= 1 u + 1500 - 510
= 1 u + 990
Difference in the volume of coffee between Gabby and Lynn in the end
= 7 p - 4 p
= 3 p
3 p = 990 - 510
3 p = 480
1 p = 480 ÷ 3 = 160
Volume of coffee that Gabby had at first
= 7 p + 510
= 7 x 160 + 510
= 1120 + 510
= 1630 mℓ
Answer(s): 1630 mℓ
