Question 1016765
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Meredith describes to Liza two purchases she made."On Monday, I bought 39 book and 21 CDs for $396. 
On Tuesday, at the same prices, I bought 52 books and 28 CDs for $518." 
Liza thought about the numbers and said "That's impossible!" Is Liza correct? Assume that all books cost the same amount. Explain.
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If you write the system of equations which describes the two purchases, you will see that the coefficients of 
the system are proportional with the proportionality coefficient of {{{4/3}}}: {{{52/39}}} = {{{28/21}}} = {{{4/3}}}. 

But the ratio of the right sides (that are totals on Monday and Tuesday) is not {{{4/3}}}.

In the terms of the equations, this system is inconsistent.
See the lesson <A HREF=http://www.algebra.com/algebra/homework/coordinate/lessons/Geom-interpret-of-the-lin-system-of-two-eqns-with-two-unknowns.lesson>Geometric interpretation of the linear system of two equations in two unknowns</A> in this site.

You may see it (exactly as Liza did) without writing the system explicitly.
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