SAT Math Practice Question #143 (Foundational (530)) | Test Citadel
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SAT Math Difficulty: Foundational (530)

Digital SAT Math Practice Question #143

Test your problem-solving accuracy on this official-caliber item. Select an answer choice to check your reasoning instantly.

The mean (average) of four numbers is 15. If three of the numbers are 10, 12, and 20, what is the fourth number?
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Socratic AI Engine Step-by-Step Derivation
0ms Precomputed
Tactical Insight (Hint 1)

Break down the given equation or algebraic constraints step-by-step. Isolate the target variable before substituting known quantities.

Elimination Framework (Hint 2)

Elimination Shortcut: Check the extremes or test answer choices starting with C to binary search the correct magnitude.

Masterclass Solution & Distractor Trap Analysis

Whenever the SAT gives you the 'mean' (or average) of a set of numbers, your very first instinct should be to find the TOTAL sum of those numbers. Here is the magic formula: Sum = Mean \(\times\) Number of items. Step 1: Find the total sum ...

Distractor Analysis: Trap choice eliminates careless test-takers who confuse roots with coordinates...

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