Question

In a puzzle-solving competition, Liza can take help for a question. As Liza is struggling, help her answer the question.

• A. 8
• B. 13
• C. 9
• D. 19

Answer 1

The correct option is A 8

Let's take the first star diagram.


Adding the numbers at top, we get:
$1+9+7=17$
And adding the numbers at bottom, we get:
$3+5+2=10$
Now, $17-10=7$

Similarly, let's look at the second star diagram.


Let's look at the numbers closely.
Adding the numbers at the top, we get:
$3+7+8=18$
And adding the numbers at the bottom, we get:
$1+4+2=7$
Now, $18-7=11$

So, basically the logic is that in each star diagram, the number in the center equals the difference of the sum of the top three numbers and the sum of the bottom three numbers.


Let's look at the third star diagram now.
Adding the numbers at the top, we get:
$6+5+9=20$
Adding the numbers at the bottom, we get:
$2+7+3=12$
Hence, $20-12=8$
Hence, the missing number will be 8.