Question

Complete the following series:

$100,25,64,49,36,?,16$

• A. $81$
• B. $64$
• C. $25$
• D. $9$

Answer 1

The correct option is A $81$

There are two alternate series :
$100256449368116$
$\downarrow \downarrow \downarrow \downarrow \downarrow \downarrow \downarrow$
${10}^2{5}^2{8}^2{7}^2{6}^2{9}^2{4}^2$
Series I : $100,64,36,16$ (squares of even numbers in decreasing order).
Series II : $25,49,81$ (squares of odd number in increasing order)