Answer:
Width of the model is:
17.5 in
Explanation:
The length of the classroom is 2.4 times its width.
Length=2.4×width
The length of the student's model is 42 in.
Let w be the width of student's model.
By using the equation Length=2.4×width , we get
42=2.4×w
⇒

⇒ w=17.5
Hence, width of the model is:
17.5 in