SSC CGL 2024 PYQ — Question 65

The correct answer is option 4 i.e. 50.

The mean proportional (or geometric mean) of two numbers a and b is given by the formula:  

$x = \sqrt{a \times b}$

30  is the mean proportional of  18  and  A.

⇒ 30² = 18 × A

⇒ 900 = 18A

⇒ A = 900 / 18 = 50