Question

A person 2 m tall casts a shadow 10 m long. At the same time, a building casts a shadow 80 m long. How tall is the building ?

Answer 1

this is a ratio question. The answer is 16 m

Explanation:

The persons height to shadow length ratio is 2 : 10

We want to know what the height of the building is when the shadows length is 80.

Let H represent height:

Persons ratio:

2 : 10

Buildings ratio:

H : 80

In other words for every 2 meters height a 10 m shadow is casted so we want to know how many of this ratio can fit into the building:

Let’s find the equivalent ratio:

80/10=8

That means 8 of the persons ratio makes up the building. Let’s find the height of building by 2*8=16.

therefore the building is 16m tall.

Answer 2

The building is 16 m tall.

Explanation:

x/2 = 80/10

10x=160

10x/10 = 160/10

x=16