Answer:
The answer is B) 11.
Step-by-step explanation:
We can solve this by making an expression to represent the situation. Let x = the number of student books in the box (what we're looking for):
[tex]2.3x + 4.3 + 0.4 = 30[/tex]
[tex]2.3x + 4.7 = 30[/tex]
[tex]2.3x + 4.7 - 4.7 = 30 - 4.7[/tex]
[tex]2.3x = 25.3[/tex]
[tex]2.3x/2.3 = 25.3/2.3[/tex]
[tex]x = 11[/tex]
