Question

The height of a stack of books, h inches is directly proportional to the number of books, n . The height of a stack of 10 books is 12 inches.

-Find the constant of proportionality
-Write and equation that relates to HandN
-Find the height of a stack of 24 books

Answer 1

y=kx is the direct variation formula. Inserting the information and variables from this scenario we get h = kn.
12 = k*(10) First solve for 'k', the constant of proportionality by dividing by 10.
1.2 = k
Next write the equation using this k and the h & n.
h = 1.2*n
Now we want to find the height if we have 24 books so plug 24 in for n.
h = 1.2 * 24
h = 28.8 inches