[islandsssol]

The rate constant for bacterial growth is 0.1 day-1. If the likely number of a given bacteria needed to cause an infection is 1000000 how long would you store a food with an initial load of a) 1 bacteria and b) 1000 bacteria?

I think I'm supposed to use this equation

Ln(Qa)=ln(Qa)0-kt

Can you help me with this?

[curiouscat]

Your eq. (signs?) seems wrong.

This will cause decimation not growth.

In any case, you know k, Q and Q0.

Find t.

[islandsssol]

   ln(1000000) = ln(1) - 0.1t

not like this?

[curiouscat]

   ln(1000000) = ln(1) - 0.1t

not like this?

Not unless you like working with  negative times 

But close....

[islandsssol]

I know what you are meaning, but the teacher put this equation like this, and I get negative days from this, as expected, but what do you suggest is the right way?