# On Tuesday, a store sold 12 compact discs, 5 cassettes, and 9 videos. On Wednesday, the store sold 19 compact discs, 3 cassettes, 9 videos and 35 concert tickets. Costruct a matrix that shows...

On Tuesday, a store sold 12 compact discs, 5 cassettes, and 9 videos. On Wednesday, the store sold 19 compact discs, 3 cassettes, 9 videos and 35 concert tickets. Costruct a matrix that shows the number of items sold, organized by day and product.

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### 2 Answers

In order to construct this matrix, we must first decide on how we wish to organize the data. How you choose to do so doesn't particularly matter so long as you use it consistently if you use this matrix to later solve a mathematical problem.

For this case, we will assign rows to the different days, and columns to the different types of media. Therefore, the matrix should be of this form:

# Discs on Tues. # Discs on Wed.

# Cassettes on Tues. # Cassettes on Wed.

# Videos on Tues. # Cassettes on Wed.

# Tickets on Tues. # Cassettes on Wed.

Finally, substituting the data we have:

`[[12,19],[5,3],[9,9],[0,35]]`

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### User Comments

Let us construct the matrix by methodically putting days in columns, and sold items in rows. The result would then be a 4 × 2 matrix with assignments like this:

Tuesday Wednesday

---------- -----------

no. of discs no. of discs

no. of cassettes no. of cassettes

no. of videos no. of videos

no. of concert tickets no. of concert tickets

and then, the result matrix (R) will be represented as:

`R = [[12,19],[5,3],[9,9],[0,35]]`

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