Status: Waiting for your answer. Formula: Given: There are 19 cells of a shigella flexneri colony.This colony has a double rate of 2.4 hours within an optimum medium. Find: Use the formula above to calculate the time it would take for the given colony to grow to 600000 cells within an optimum medium. Calculate the solution for 't' to the nearest tenth using logarithms. Solution: t = hours