The pharmacist has a 3.6 L bottle of cough syrup. If she fills a bottle that is 1,500 ml, how many ml of cough syrup does the pharmacist have left? (1 L = 1,000 ml)

21 ml
150 ml
1,360 ml
2,100 ml

The pharmacist has a total of 3.6 L * 1,000 ml/L = <<3.6*1000=3600>>3600 ml of cough syrup.

After filling a bottle with 1,500 ml, the pharmacist has 3600 ml - 1500 ml = <<3600-1500=2100>>2100 ml of cough syrup left. Answer: \boxed{2,100 \text{ ml}}.

To find out how much cough syrup the pharmacist has left, we need to subtract the amount of cough syrup used from the initial amount.

Given that the pharmacist has a 3.6 L bottle of cough syrup, which is equivalent to 3,600 ml, and she fills a bottle that is 1,500 ml, we can find the remaining amount of cough syrup by subtracting 1,500 ml from 3,600 ml.

3,600 ml - 1,500 ml = 2,100 ml

Therefore, the pharmacist has 2,100 ml of cough syrup left.