Acertain bacterias population is cut in half every 6 hours. after 2 full days, there are 400 bacteria in the culture. how many bacteria were in the culture at the start of the day?

In this question, the population of the bacteria will become half after 6 hours and the duration (2 days=48 hours) and the final amount of bacteria (400 bacteria), To find the number of bacteria at the start(initial number), the calculation would be:

Final number = initial number / 2^(duration/6hours)
400= initial number / 2*(48/6)
initial number = 400 * 2^8= 102,400

First step is to get rid of the square root. remember that a square root is the same as raising to the (1/2) power. see below: multiply exponents per exponent rules to get: remember you subtract exponents from the denominator and add exponents in the numerator so: simplify further: so a is the correct choice. if you don't understand this google exponent rules and it will you understand. look at the image results.