Every hour the number of bacteria in a sample doubles. If the original number of bacteria is 100, and 50 bacteria are removed every two hours, after five hours, there are

Correct option is B

The original number of bacteria = 100
After one hour the number of bacteria = 200
Since every hour bacteria in a sample doubles
So after two hours, the number of bacteria = 400
But after every two hours, 50 bacteria are removed so the number of bacteria after two hours = 400 - 50 = 350
In the third hour number of bacteria = 700
In the fourth hour the number of bacteria = 1400
After removal of 50 bacteria = 1400 - 50 = 1350
In the fifth hour the number of bacteria = 2700