Word Problem: Finding growth-rate value for bacteria culture

[growold61]

The number of bacteria present in a culture after t minutes is given as B=25e^kt. If there are 218 bacteria present after 2 hours, find k (round out four places).

Please Help! Am I looking for the ratio? I am not sure how to work out this WORD PROBLEM!

 

[galactus]

Set B=218 and t=2 and solve for k.

 

[stapel]

I am not sure how to work out this WORD PROBLEM!

The only difference between this exercise and the "solve the exponential equation" exercises you worked on previously is that here the equation is dressed up inside a "word problem". But the process is the exactly the same:

You've been given an equation with three unknowns, and have been provided values for two of the unknowns. You have been asked for the value of the third unknown. So plug the two given values in for the two specified variables, and solve the resulting exponential equation for the remaining variable.

If you get stuck, please reply showing all of your work and reasoning. Thank you!

Eliz.