- a.80 feet
- b.100 feet
- c.120 feet
- d.90 feet
No option is correct as printed — this question is disputed.
PSC cancelled this question in the final key, evidently because the English and Bengali versions ask different things: the English version asks for the height of a tower whose shadow is 180 feet, while the Bengali version asks for the shadow of a 180-foot tower. English version: height and shadow are proportional at the same time of day, so $\frac{64}{96}=\frac{h}{180}$, giving $h=\frac{64\times180}{96}=120$ feet (option C). Bengali version: shadow $=\frac{96}{64}\times180=270$ feet, which is not among the options. The method - similar triangles, height : shadow constant - is what matters. CANCELLED BY PSC: the final answer key (Notice No. 628-PSC/Con(Q), 30 Sept 2021) shows '*' for this question (Set C Q183); the English and Bengali versions of the booklet ask different things. correct_answer 'C' (120 feet) is the mathematically correct answer to the English version only - it is not an official answer.