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A video store specializes in three types of movies: children's, American West, and horror. It's known that:

60% of children's movies plus 50% of westerns account for 30% of all movies.
20% of children's movies plus 60% of westerns plus 60% of horror movies represent half of all movies.

User Joycollector
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2 Answers

26 votes
26 votes

Final answer:

The question requires solving a mathematical problem involving proportions and percentages in the context of a video store's movie inventory. It necessitates high school-level algebra to interpret the given data and solve for the number of movies in each genre.

Step-by-step explanation:

Analysis of Movie Categories and Percentages

The question presents a mathematical scenario within the context of a video store's movie inventory and asks for an interpretation of proportions among different movie genres. Students must use their knowledge of percentages and algebra to solve the system of equations that arises from the given data. The store specializes in children's movies, American West (westerns), and horror movies. We are told that 60% of children's movies plus 50% of westerns make up 30% of all movies at the store. Another piece of information indicates that 20% of children's movies, 60% of westerns, and 60% of horror movies together represent 50% of the total movies available.

Such problems are typical of a high school mathematics curricula where students are expected to handle percentages and linear equations. We can denote the total number of children's movies as C, westerns as W, and horror movies as H. We then form two equations: 0.6C + 0.5W = 0.3(C + W + H) and 0.2C + 0.6W + 0.6H = 0.5(C + W + H). To solve for the exact values of C, W, and H, we would need additional information or another equation. The solution to these types of problems typically involves the use of algebraic techniques such as substitution or elimination.

Understanding proportions and their relation to real-world contexts like this video store example is essential for students, as these skills are highly relevant in various fields, including business, economics, and various scientific disciplines. Moreover, this knowledge forms a fundamental part of the quantitative reasoning skills necessary for SAT and AP mathematics tests.

User James Legan
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23 votes
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X, y, z denote children's movies, western movies, and horror movies, respectively. The related system of equations is formed and solved.


\left\{\begin{matrix} \qquad\qquad\ (60)/(100)x + (50)/(100)y =(30)/(100)(x+y+z)\\ (20)/(100)x+ (60)/(100)y+ (60)/(100)z= (1)/(2)(x+y+z) \\ \ \ \ x+100=y \end{matrix} \right.\

Simplifying the system of equations, we have


\left\{\begin{matrix} 3x + 2y -3z=0\\ -3x+ y+ z= 0 \\ \ \ \ x+100=y \end{matrix} \right.\ \ \Longrightarrow \ \left\{\begin{matrix} 5x-3z=-200\\ -2x+ z= -100 \end{matrix} \right.\


\ \ \ 5x-3z=-200\\\underline{-6x+3z=-300} \ \Rightarrow \ x=500\\\ \ -x+0= \ 500


y&=500+100=600\\ z&=3(500)-600=900

The video store has 500 children's movies, 600 westerns and 900 horror movies.

User Benrg
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