At 5 pm there were 20 bacterial cells in a test tube Knowing

At 5 pm, there were 20 bacterial cells in a test tube. Knowing that the generation time is 6 minutes, how many bacteria do you expect there will be in the test tube at 5:30 pm? Bacteria reproduce by binary fission, in which one bacterium becomes two bacteria.

120 cells

640 cells

1280 cells

56 cells

Solution

The correct answer is 640 cells.

Explanation:

x = X * 2 ^n

where x = number of bacteria at the end of time interval i.e 5:30 pm

X = number of bacteria at the beginning of time interval i.e 5 pm = 20

n= number of generations

Generation time (g) = 6 minutes

Time interval( t) = 30 minutes

n= Time interval (t) / generation time (g)

= 30/6 = 5

Substituting the values we get,

x= 20 * 2^5

= 640 cells .( ans )