Since B=Ae^kt, Given that there are 350 bacteria present initially and there are 1700 after 4 days , find the number present after 1 week
Since e^0 = 1, A = 350
Now use the other data point and you have 350e^(4k) = 1700
Now you know A and k, so plug in t=7
Or, since e^(7k) = (e^(4k))^(7/4)
B(7) = 350*(1700/350)^(7/4)