MathDB

9

Part of 2008 AMC 10

Problems(2)

Integer Fraction Conditions

Source: AMC 12 2008A Problem 5

2/17/2008
Suppose that \frac {2x}{3} \minus{} \frac {x}{6} is an integer. Which of the following statements must be true about x x? <spanclass=latexbold>(A)</span> It is negative.<spanclass=latexbold>(B)</span> It is even, but not necessarily a multiple of 3. <span class='latex-bold'>(A)</span>\ \text{It is negative.} \qquad <span class='latex-bold'>(B)</span>\ \text{It is even, but not necessarily a multiple of }3\text{.} <spanclass=latexbold>(C)</span> It is a multiple of 3, but not necessarily even. <span class='latex-bold'>(C)</span>\ \text{It is a multiple of }3\text{, but not necessarily even.} <spanclass=latexbold>(D)</span> It is a multiple of 6, but not necessarily a multiple of 12. <span class='latex-bold'>(D)</span>\ \text{It is a multiple of }6\text{, but not necessarily a multiple of }12\text{.} <spanclass=latexbold>(E)</span> It is a multiple of 12. <span class='latex-bold'>(E)</span>\ \text{It is a multiple of }12\text{.}
AMC
Quadratic

Source: AMC 10 2008B Problem 9

3/1/2008
A quadratic equation ax^2\minus{}2ax\plus{}b\equal{}0 has two real solutions. What is the average of the solutions? (A)\ 1 \qquad (B)\ 2 \qquad (C)\ \frac{b}{a} \qquad (D)\ \frac{2b}{a} \qquad (E)\ \sqrt{2b\minus{}a}
quadraticsVietaalgebraAMC