music1031
Answered

A certain bacteria doubles the number of its cells every 20min. A scientists puts 50 cells in a culture desk. How many cells will be in the culture dish after 2h.

Answer :

rabinshrestha41
Given:
total bacteria cells = 50
time given = 2 hours = (2 * 60) minutes 
                               = 120 minutes.
Now,
According to the question,
the bacteria cells replicate itself in 20 minutes.
So,
In 20 minutes, the bacteria cells replicate 1 time
In 1 minute, the bacteria cells replicate 1/20 times
In 120 minutes, the bacteria cells replicate (1/20)*120 times
                                                               = 6 times
So, 
In 120 minutes , there will be (50 * 6) bacteria cells
                                           = 300 bacteria cells

So, there will be 300 cells in the culture dish after 2h
MichaelLiu
Every 20 min, the bacteria doubles. So there should be 6 doubling periods in 2 hrs. (2hrs / 20 min = 6) So now you just have to double 50, 6 times. This is essentially 50* [tex] 2^{6} [/tex] which is equal to 50*64=3200. 3200 is the number of bacteria after you doubled 50, 6 times.