Question

Fill in the missing number:
3, 15, 35, ?, 99, 143

• A. 68
• B. 58
• C. 63
• D. 45
• E. None of the above

Answer 1

The correct option is C 63

43 = $2^2$ - 1; 15 = $4^2$ - 1; 35 = $6^2$ - 1
99 = ${10}^2$ - 1; 143 = ${12}^2$ - 1
$\therefore$ The missing figure should be $8^2$ - 1 = 63.