On Saturday, the store sold 17 reams of paper and 12 DVDs for a total of $136.50. On Sunday, the store sold 8 reams of paper and 21 DVDs for a total of $141. Determine the cost of each ream of paper and each DVD

Respuesta :

The cost of each ream of paper is $4.5 and that of DVD is $5.

What is a system of linear equations?

A system of linear equations is a group of  equations having same number of variables and degree.

For the n number of variables n number of equations are required.

On the basis of number of solutions a system of equations can be classified as consistent and inconsistent.

Given that,

The price for 17 reams of paper and 12 DVDs is $136.50.

And, the price for 8 reams of paper and 21 DVDs is $141.

Suppose the cost of each ream of paper be x.

And, the cost of each DVD be y.

THen, the following equations can be made for the two cases,

17x + 12y = 136.50      (1)

8x +  21y = 141            (2)

Solve these equations by multiplying equation (1) by 7 and (2) by 4 and then subtracting them as,

7(17x + 12y) - 4(8x +  21y) = 7 × 136.50 - 4 × 141            

=> 87x = 391.5

=> x = 4.5

Substitute x = 4.5 in equation (1) to get,

17 × 4.5 + 12y = 136.50

=> 12y = 136.50 - 76.50

=> 12y = 60

=> y = 5

Hence, the cost of each ream of paper and each DVD are $4.5 and $5 respectively.

To know more about system of equations click on,

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