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?

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!

Subtracting is the opposite of adding

The correct answer is 10%