A flagpole 18 meters high casts a shadow of length 45 meters. If a building under similar conditions casts a shadow of length 50 meters, what is the height of the building (in meters)?
Choose the correct choice from the following options:  A) 16  B) 20  C) 24  D) 28  E) 32

Rationale: "the height : length ratio will be equal in both cases . 18 / 45 = x / 50 x = 20 the answer is b ."
Answer: B