Solution
The correct answer is 11.25
Explanation
Let $x$ be height of the other pole.
Shadow of poles at a certain time are proportional to their lengths.
⇒ 2 : 3 :: 7.5 : $x$
⇒ $x$ = $\dfrac{7.5 × 3}{2}$ = $11.25$
Hence, the height of the other pole is $11.25$