An IV uses 10 drops to deliver 1 mL of solution (10 drops per mL). An IV is set to deliver solution at a rate of 20 drops per minute. An IV bag contains 400 mL of solution. Find the time in minutes it will take to empty the bag.

400mL * 10drops/1mL * 1min/20drops = 400*10/20 = 200 min