store is selling 5 small tables with 8 chairs for $115. Three tables with 5 chairs cost $70.

Question 1

Which system of linear equations could be used to find the cost of each table (x) and the cost of each chair (y)?
Responses

A 3x + 8y = $70; 8x + 3y = $1153x + 8y = $70; 8x + 3y = $115

B 5x + 8y = $115; 3x + 5y = $705x + 8y = $115; 3x + 5y = $70

C 5x + 8y = $115; 2x − 5y = $705x + 8y = $115; 2x − 5y = $70

D 8x + 5y = $115; 5x + 3y = $708x + 5y = $115; 5x + 3y = $70
Question 2

Determine the cost of each table (x) and the cost of each chair (y).
Responses

A x = $15; y = $5x = $15; y = $5

B x = $10; y = $5x = $10; y = $5

C x = $5; y = $10x = $5; y = $10

D x = $12; y = $3x = $12; y = $3

1 answer

To solve the problem, we first need to express the given information in the form of linear equations.

From the problem, we have:

  1. First equation: 5 small tables with 8 chairs cost $115. This can be expressed as: \[ 5x + 8y = 115 \] where \(x\) is the cost of each table and \(y\) is the cost of each chair.

  2. Second equation: 3 tables with 5 chairs cost $70. This can be expressed as: \[ 3x + 5y = 70 \]

Now we have the system of equations:

  1. \(5x + 8y = 115\)
  2. \(3x + 5y = 70\)

Now, looking at the options for Question 1, we can conclude that the correct option is: B: \(5x + 8y = 115; , 3x + 5y = 70\)


Next, let's solve the equations to determine the cost of each table (\(x\)) and each chair (\(y\)).

  1. From the first equation: \[ 5x + 8y = 115 \quad \text{(1)} \]

  2. From the second equation: \[ 3x + 5y = 70 \quad \text{(2)} \]

We can solve this system using substitution or elimination. Here we'll use the elimination method.

Start by multiplying equation (2) by 5 and equation (1) by 3, so we can eliminate \(y\):

  • Multiply (1) by 3: \[ 15x + 24y = 345 \quad \text{(3)} \]

  • Multiply (2) by 5: \[ 15x + 25y = 350 \quad \text{(4)} \]

Now we can set these up as follows: \[ 15x + 24y = 345 \quad \text{(3)} \] \[ 15x + 25y = 350 \quad \text{(4)} \]

Next, subtract equation (3) from equation (4): \[ (15x + 25y) - (15x + 24y) = 350 - 345 \] This simplifies to: \[ y = 5 \]

Now substitute \(y = 5\) back into one of the original equations. We will use equation (1): \[ 5x + 8(5) = 115 \] \[ 5x + 40 = 115 \] \[ 5x = 115 - 40 \] \[ 5x = 75 \] \[ x = 15 \]

Thus, the cost of each table \(x\) is $15 and the cost of each chair \(y\) is $5.

Now, looking at the options for Question 2, the correct answer is: A: \(x = 15; , y = 5\)

In summary:

  • The answer to Question 1 is B.
  • The answer to Question 2 is A.