How long will it take for the population to reach 1290 ?
A bacteria culture starts with 160 bacteria and grows at a rate proportional to its size. After 4 hours there will be 640 bacteria.

Question

How long will it take for the population to reach 1290 ? 
A bacteria culture starts with 160 bacteria and grows at a rate proportional to its size. After 4 hours there will be 640 bacteria.

anonymous · Answer

I think it need 7 hours and 225 seconds

anonymous · Answer

ok, 7:03':45"

anonymous · Answer

if you have an answer from your book, check whether mine is right or wrong. if it 's right, tell me and I give you my argue for that result. if it's wrong. I'm sorry, waste your time

anonymous · Answer

its wrong, but i wil give you medal for trying to help me thanks

anonymous · Answer

no need to do that. I'm ok, just try to do. and I want to know the answer ,too, would you please tell me what ' s right?