Question

Greg planted a tree that was 10% of its estimated final height. During the first year after Greg planted the tree, it grew 5 feet, making it 13 feet tall. What was its estimated final height?

Answer 1

the estimated final height is 80 ft

Explanation:

let the estimated final height = y

Initial height of tree = 10% of the estimated height

initial height = 0.1 × y = 0.1y

1st year:

The initial height grew by 5 feet to have a height of 13 feet

This is represented as:

$\begin{gathered} in\text{itial height + 5 = 13 } \\ 0.1y\text{ + 5 = 13} \end{gathered}$

solving for x:

$\begin{gathered} \text{subtract 5 from both sides:} \\ 0.1y\text{ + 5 - 5 = 13 - 5} \\ 0.1y\text{ = 8} \\ \\ \text{divide both sides by 0.1:} \\ \frac{0.1y}{0.1}\text{ =}\frac{8}{0.1} \\ y\text{ = 80} \end{gathered}$

Hence, the estimated final height is 80 ft