MathRevolution
[GMAT math practice question]
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Points \(A, B, C\), and \(D\) lie on the number line as shown in the figure above. If \(AC=BD\) and \(AB=\frac{BC}{5}\), what is the value of \(C\)?
A. \(\frac{7}{14}\)
B. \(\frac{8}{14}\)
C. \(\frac{9}{14}\)
D. \(\frac{10}{14}\)
E. \(\frac{11}{14}\)
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If\(AB = \frac{BC}{5}\), then \(BC\) is 5 times bigger than\(AB\)
Let \(BC = 5x\)
Thus \(AB = x\)
And \(AC = 6x\)
\(AC = BD = 6x\)
They share middle part \(BC = 5x\)
\(CD\)?
\(= x\)
Both segments above the line are equal
They share \(5x\). One has another segment of length
x (AB). The other segment must have a segment with length x, too. That's
CD.
\(CD = AB = x\)
Length of whole segment \(AD = (x + 5x + x) = 7x\)
Length of whole segment also \(AD = (\frac{2}{3} - \frac{1}{2}) = \frac{1}{6}\)
\(7x = \frac{1}{6}\)
\(x = \frac{1}{42}\)
Point \(C = D - \frac{1}{42}\)
\(C = (\frac{2}{3} - \frac{1}{42}) = (\frac{28}{42} - \frac{1}{42}) = (\frac{27}{42}) = \frac{9}{14}\)
Answer C
Bunuel , would you please check the OA? Thanks in advance.