Final answer:
A tree that grows 18 inches (1.5 feet) per year will take 16 years to grow from its current height of 12 feet to a height of 36 feet.
Step-by-step explanation:
To determine in how many years a tree that is currently 12 feet tall and grows 18 inches per year will reach 36 feet, we can set up a simple algebraic equation. First, we need to convert the growth rate from inches to feet, as the height we want to achieve is in feet. Since 18 inches is equivalent to 1.5 feet (because there are 12 inches in a foot), we can now calculate the total growth needed for the tree to reach 36 feet. The tree needs to grow from 12 feet to 36 feet, which is a total growth of 36 feet - 12 feet = 24 feet. At a rate of 1.5 feet per year, we can divide the total growth needed by the growth rate per year to obtain the number of years it will take:
24 feet ÷ 1.5 feet/year = 16 years.
Therefore, it will take the tree 16 years to reach a height of 36 feet.