Function f is an exponential function:

what are the ratios of outputs for any 2 inputs that are 4 apart?

The answer would be 18
The problem asks ratio of two inputs that are 4 apart. Ratio means that it is asking you to divide the second number(x2) with the first number(x1). Two inputs that are 4 apart can be translated as x2-x1 = 4.
Let use x2=4 and x1=0Then the ratio of f(x) would be:f(x2)/f(x1)= f(4)/ f(0)=       ---> get the value from the table. f(4)= 48, f(0)=348/3= 16