To re-phrase this: 50 is a certain percent of 90.
this can be written mathematically as 50=x%*90
let's divide both sides by 10:
5=x%*9
and divide both sides by 9:

which in decimals is approximately 0.56 (but not exactly).
so 0.56=x%
and the x then 56
so 50 is
approximately 56% of 90:
exactly 56%of 90 is 50.4
Because it is a 90° angle and the legs are congruent, the legs intersect with the hypotenuse at the same angle, so the other, unnamed angle at the bottom left is equal to x.
Now we can state that:
2x + 90 = 180
2x = 90
x = 45
Let
y-------> number of books read during the month 
x------> number of picture of a book
we know that

in this problem
for 
calculate y

therefore
the answer is
The number of books read during the month
is 
Answer:
The answer is the second one because it is less than or equal to 35