A cell's division time is 1 minute. In 20 minutes, a culture tube (culture medium) is `1//8^(th)` filled with cells. When the tube will be fully filled?

Options

A. (a) 21 minutes
B. (b) 23 minutes
C. (c) 60 minutes
D. (d) 160 minutes

Answer

B

Explanation

In 20 mins. Culture tube `1//8^(th)` filled with cells. Each cell divides every minute producing two daughter cells.
Hence, 21 min `=(1)/(8)xx2=(1)/(4)`
In 22 min `(1)/(4)xx2=(!)(2)`
In 23 min `(1)/(2)xx2=1`
That means, in 23 minutes the culture tube will be completely filled.