Question: From a bacteria stock you serially dilute 1/100 2 times, then serially dilute 1/10 2 times.  From this last tube you plate 100 ul, which produces 156 colonies the next day.  What was the the number of Colony Forming Units (CFU)/ml in the original stock solution?

Please enter your answer in scientific notation, with one decimal, using “E” notation.  For instance, 22,360 would be written as “2.2E4”