Question

if it takes 20 minutes to run a batch of hundred pills how many minutes will it take to run a batch of 50

Answer 1

For the answer, you want to divide the minutes by two, since you're dividing the number of batches by 2. 
So your answer is 10

Answer 2

The answer is simple. Take the amount of time that it took for one hundred and divide it by two, because you want to find out how much time it takes to run out of 50. Calculate it out and you get 10 minutes!
Hope this helps! Brainliest is always welcome!