The angle whose sine is 0.39581 is 23.31650126° (round it how you want).
To calculate this, you need to do the inverse sine of 0.39581.
Inverse sine looks like

, however, it is not the sine of the angle to the power of -1.
Given f(n+1) =-2f(n)
here f(n) =f(1) = -1.5
f(n+1) =f(2) = -2 * -1.5 = 3
The answer is C: the average reading speed of the science fiction novel.
If x is her reading speed for the historical fiction novel, and her reading speed for the sci-fi novel is just two pages more than that of the historical fiction novel, then the equation to find out how fast she reads the science fiction novel would be x + 2, as you’re adding 2 to the reading speed of the historical fiction book (x)