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The journey of every round

Every round-trip in the corpus is public. Open one to see the prompt, the zero-point index, the baseline response, the enhanced response, and how each grader read the difference. Leave a comment if a grader's reading lands — or doesn't.

#110121 May 26

Given f(x) = (x - 4) / 3, state the inverse function f^(-1)(x). Give the inverse in explicit form.

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#110021 May 26

State the distributive law of intersection over union for three sets A, B, C. Give the identity in set notation.

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#109921 May 26

State the formula for the volume of a sphere of radius r. Give the formula in exact form using pi.

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#109821 May 26

Given the recursive sequence a_1 = 2 and a_(n+1) = 3 a_n - 1, compute a_4. Give the exact integer.

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#109721 May 26

Compute the limit of the sequence a_n = (5n^2 + 2) / (2n^2 - n + 4) as n approaches infinity. Give the exact value.

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#109621 May 26

Compute the sum of the arithmetic series 3 + 7 + 11 + ... + 99. Give the exact integer.

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#109521 May 26

Compute the sum of the infinite geometric series 1 + 1/3 + 1/9 + 1/27 + ... Give the exact value.

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#109421 May 26

Is the repeating decimal 0.999... equal to 1? State the exact value and justify using a geometric-series argument.

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#109321 May 26

How many distinct arrangements are there of the letters in the word "STATISTICS"? Give the exact integer.

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#109221 May 26

Compute the number of permutations of 9 distinct objects taken 4 at a time, P(9, 4). Give the exact integer.

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#109121 May 26

Compute 7! (seven factorial). Give the exact integer.

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#109021 May 26

Compute the binomial coefficient C(10, 4). Give the exact integer.

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#108921 May 26

Compute the least common multiple of 30 and 45. Give the exact integer.

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#108821 May 26

Compute 5^6 mod 11. Give the exact integer in the range 0 to 10.

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#108721 May 26

State the smallest prime factor of 943. Give the exact integer.

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#108621 May 26

Compute the greatest common divisor of 360 and 84 using the Euclidean algorithm. Give the exact integer.

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#108521 May 26

A fair six-sided die is rolled twice. Compute the expected value of the sum of the two rolls. Give the exact value as a rational number.

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#108421 May 26

A disease affects 2% of the population. A test is 90% sensitive and 95% specific. Someone tests positive. Compute the probability they actually have the disease. Give the exact value.

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#108321 May 26

A prior P(H) = 0.3 and likelihood P(E|H) = 0.9, with P(E|not H) = 0.2. Compute the posterior P(H|E) using Bayes' theorem. Give the exact value.

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#108221 May 26

State Bayes' theorem expressing P(A|B) in terms of P(B|A), P(A), and P(B). Give the formula.

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#108121 May 26

Compute the limit of (x^2 - 9) / (x - 3) as x approaches 3. Give the exact value.

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#108021 May 26

Evaluate the definite integral of (4x - 3) from x = 1 to x = 5. Give the exact value.

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#107921 May 26

Differentiate h(x) = cos(5x^3 - 2x) using the chain rule. Give the exact derivative.

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#107821 May 26

Evaluate the indefinite integral of 5x^4 + 2e^x with respect to x. Give the antiderivative and include the constant of integration.

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