Question

The function f(x) = 50 • 1.5x represents the number of bacteria after x days. Find the average rate of change from 0 days to 4 days. Round values to the nearest whole number. A. 83 B. 203 C. 51 D. 4

Answer 1

f(x) = 50 * 1.5^x (not 1.5x):  # of bacteria present.

Average Rate of Change from 0 days to 4 days is 

f(4) - f(0)        50(1.5^4 - 1.5^0)       bacteria
------------- = -------------------------- ------------------
     4-0                       4                      day

     50(5.0625 - 1)
= ----------------------- = 51 bacteria per day = average rate of change 
                4