A culture of 10 bacteria in a petri dish double every 40 minutes. How many bacteria will there be after 4 hours?

Question

step by step please solution please :)

Answer 1

The table of increase looks something like this:

Time (minutes) 0 40 80 120 160 etc

# Bacteria 10 20 40 80 160

So, you will have a factor of 2 each time. If B = # Bacteria & t = time

Let B = (10)*2^(t/40) then each time the time increases by 40 minutes, you double the number.

Check at each point to be sure it is accurate!

Answer 2

A(t) = 10(2)^240/40 4 hrs. = 240 min.

A(t) = 10(2)⁶

A(t) = 10(64)

A(t) = 640