Your answer is B F(x) * (0.5)^x
Is there another part to your question
Answer:
The graph in the attached figure
Step-by-step explanation:
Let
x -----> the number of solved puzzles
y -----> the number of solved riddles
we know that

The solution of the inequality is the shaded area above the solid line 
The slope of the solid line is negative 
The y-intercept of the solid line is the point (0,4)
The x-intercept of the solid line is the point (2,0)
therefore
The graph in the attached figure
54/(2X3)=54 divided by 6, =9 square root of 9 is 3
n=3