Algebra practice question

Answer: 12

The three numbers total 3 × 10 = 30. So x = 30 − 7 − 11 = 12.

Common wrong answers

If you answered 9

9 is the average of 7 and 11, ignoring x's role in the total.

If you answered 10

10 is the average itself, not the missing number.

If you answered 30

30 is the total of the three numbers, not x.

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