Question

A special die has a number on each face. The sums of the opposite faces are all equal. Five of the numbers are 5,6,9,11, and 14. What number is on the sixth face?

Answer 1

The missing number is 15.

Explanation:

The sum of the opposite faces is 20, because 14 + 6 = 20 and 11 + 9 = 20, so we just need to find the answer to the equation

5 + x = 20

Solving for x, we have

x = 20-5

x = 15.

Therefore, the missing number is 15.