Question

Finding the missing number (?) in the following arrangement: - Box 1: Top corners (15, 2), Bottom corners (5, 6), Middle = 40 - Box 2: Top corners (9, 7), Bottom corners (4, 5), Middle = 30 - Box 3: Top corners (17, 13), Bottom corners (13, 12), Middle = ?

Accepted Answer

D. Pattern across the boxes: $$	ext{Middle} = \frac{	ext{Top Left} - 	ext{Bottom Left}}{2} 	imes (	ext{Top Right} + 	ext{Bottom Right})$$ Box 1: $\frac{15 - 5}{2} 	imes (2 + 6) = 5 	imes 8 = 40$ Box 2: $\frac{9 - 4}{2} 	imes (7 + 5) = 2.5 	imes 12 = 30$ Box 3: $\frac{17 - 13}{2} 	imes (13 + 12) = 2 	imes 25 = 50$

Number Puzzle Box

Explanation

Practise this under exam conditions