Which number will replace the question mark ?
2025
Which number will replace the question mark ?
- A.
8
- B.
7
- C.
6
- D.
5
Attempted by 39 students.
Show answer & explanation
Correct answer: D
Answer: 5
Key idea: The centre number equals the absolute difference between the sum of the even point numbers and the sum of the odd point numbers.
First star (given): point numbers 1, 6, 2, 3, 4. Sum of evens = 6 + 2 + 4 = 12. Sum of odds = 1 + 3 = 4. Difference = |12 - 4| = 8 (matches the centre).
Second star (given): point numbers 4, 9, 8, 2, 11. Sum of evens = 4 + 8 + 2 = 14. Sum of odds = 9 + 11 = 20. Difference = |14 - 20| = 6 (matches the centre).
Third star (target): point numbers 10, 7, 5, 5, 2. Sum of evens = 10 + 2 = 12. Sum of odds = 7 + 5 + 5 = 17. Difference = |12 - 17| = 5, so the missing centre number is 5.
Therefore the missing number is 5.