Answer:
The number of bacteria in 0.25 mL is 6.25 x 10^3.
Step-by-step explanation:
5 liter flask contains 1.25 x 10^8 bacteria.
So, 1liter flask contains = [tex]\frac{1.25 \times 10^8}{5} =2.5\times 10^7[/tex]
Now
0.25 mL contains = [tex]2.5\times 10^7 \times0.25\times 10^{-3} = 6.25\times 10^3[/tex]