SAT Math Practice Question #2510 (Medium) | Test Citadel
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SAT Math Difficulty: Medium

Digital SAT Math Practice Question #2510

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Adding the value 15 to a dataset increases the mean from 10 to 11. How many values were in the original dataset?
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Socratic AI Engine Step-by-Step Derivation
0ms Precomputed
⚡ 15-Second Desmos Speed Hack

Desmos / Statistical Reason: Filter conditional probability denominators carefully — 'out of what total' is always the key.

Masterclass Solution & Distractor Trap Analysis

Let $n$ be original count: sum $= 10n$. New mean: $\frac{10n + 15}{n + 1} = 11 \implies 10n + 15 = 11n + 11 \implies n = 4$....

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

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