Chain Rule Q45

45. A flagstraff 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 conditions will be:

[A] 10 m

[C] 17.5 m

[B] 12.5 m

[D] 21.25 m

Answer : B

Explanation :

Let the height of the building be x metres.

Less lengthy shadow, Less is the height (Direct Proportion)

40.25 : 28.75 :: 17.5 : x

40.25 x x = 28.75 x 17.5

x = (28.75 x 17.5) 40.25

x = 12.5