Algebra practice question

Answer: 9

(4 + 9 + x + 2x)/4 = 10 gives 13 + 3x = 40, so x = 9.

Common wrong answers

If you answered 18

18 is 2x.

If you answered 27

27 is 3x, forgetting to divide by 3.

If you answered 13.5

13.5 comes from 2x = 27.

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