NIELIT 2017 July Scientist B - Section A: 10

Question

A flagstaff $17.5$ m high casts a shadow of length $40.25$ m. The height of the building, which casts a shadow of length $28.75$ m under similar condition will be?

• A. $10$ m
• B. $12.5$ m
• C. $17.5$ m
• D. $21.25$ m

Answer 1

Let the height of the building be x metres.

According to question we understand Less lengthy shadow Less in height (Directly Proportional)

so, 40.25 : 17.5 :: 28.75 : x

=> x   = (28.5 * 17.5) / 40.25 = 12.5 metres

So, correct answer is B

Answer 2

shadow of length 40.25 m = 17.5 m high

shadow of length 1 m = 17.5/40.25 m high

shadow of length 28.75 m = 28.75×17.5/40.25= 12.5 m high