# I planted a 3 ft tree that has grown the same amount each year.at the end of the third year , the tree was 1/5 taller than it was at the end of the second year .the tree is now 18 feet tall. How many years ago did I plant the tree?

##### 1 Answer

Jul 20, 2018

15 years ago

#### Explanation:

let

at the end of year 2, height

at the end of year 3, height

but we are also told that

combining eqns (2) and (3) (both equal to

Total growth since planting

At 1 ft/year this has taken 15 years