Question

You plant a tree that is 42 inches tall. After one year, the tree is 47 inches tall. Which expression describes the percent increase of the tree's height?

Answer 1

This is how you would set it up

42 47
----- -----
100 x
Then, cross multiply. You should get this:
42x = 4700

Then, solve that problem
42x = 4700
----- -------
42 42

x = 111 < (the answer turns out as a decimal but you should take the whole number)

Then subtract 111 and 100
111 - 100 = 11

Answer - 11%

Hope this helps!