2020 AMC 12A Problem 17


The vertices of a quadrilateral lie on the graph of y=lnxy = \ln x , and the xx -coordinates of these vertices are consecutive positive integers. The area of the quadrilateral is ln9190\ln \frac{91}{90} . What is the xx -coordinate of the leftmost vertex?

(A) 6(B) 7(C) 10(D) 12(E) 13\textbf{(A)}\ 6\qquad\textbf{(B)}\ 7\qquad\textbf{(C)}\ 10\qquad\textbf{(D)}\ 12\qquad\textbf{(E)}\ 13


Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.

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Category: AMC 12A
Points: 3
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