Question

Bacterial cell divides in every minute. It takes one hour to fill up a cup. How much time will be taken to fill half the cup?

• A. 59 minutes
• B. 30 minutes
• C. 60 minutes
• D. 29 minutes

Answer 1

Answer: (A)

59 minutes

• A bacterial cell divides at regular intervals under favorable condition, this is called exponential growth. Growth is by geometric progression: 1, 2, 4, 8 ........... etc.
• So, if in one minute it becomes two, then in two minutes it will become four i.e., becomes double every minute. If bacterial cells take one hour (60 minutes) to fill up a cup, then it means before one minute there were half-cup bacteria. So, bacterial cells will fill half the cup in 59 minutes.

Thus, the correct answer is option (A).