Answer:
Dec 10
Explanation:
0.25 liter = 250 ml
4 ml * 3 = 12 ml
250/12 = 20.83 days
Nov 20 - Nov 30: 11 days
Dec 1 - Dec 9: 9 days
On December 9, she can still take her 3 doses.
By December 9, she will have taken 12 ml per day for 20 days for a total of 240 ml. She has 10 ml left for Dec 10th.
On Dec 10, she will take 2 doses of 4 ml and 1 dose of 2 ml, and she will finish the medicine.