Question

A tree is standing behind a building. 2/5 of the height of the tree can be seen and the rest is hidden by the building. The building is 9 metres high. What is the height of the tree?

Answer 1

Let the height of the tree that can be seen = x m

Height of the bulding = 9 m

Total height of the tree = (x + 9) m

According to question

2/5(x + 9) = x

⇒2x + 18 = 5x

⇒5x − 2x = 18

⇒3x = 18

⇒x = 18/3 = 6

So, the height of the tree = 15 m

Answer 2

Let the height of the tree be x

then,
part hidden behind the the building = x-2x/5
= 3x/5
Given,
height of building = 9m

height of building = part of tree hidden
9=3x/5
x=(9×5)/3
x= 15 m

so, height of tree is 15 meters