Example 3: The table below shows the amount a banquet hall charges to feed different sized groups of people

Number Of People | COST
10 $200
14 $252
21 $441
23 $471

Using a linear model, what is the approximate residual value of the cost to feed 21 people
Answer Choices:
A.$8 B.$12 C.$15 D.$21 E. $34 F. $47 G. $52 H. $43 I. $32 J. $25 K. $19 L. $5

~I got K. $19 I dont understand this problem please help me i did everything with a calculator

so, what were your calculations? If we are to analyze why your answer may be wrong, show us how you got it.

I did it on a calculator and followed my teacher steps dont know how to explain

rubbish. If you followed the steps, what were they?

On moodle its a video.

To solve this problem, we are given a table that shows the amount a banquet hall charges to feed different sized groups of people. We are asked to find the approximate residual value of the cost to feed 21 people using a linear model.

To begin, we need to create a linear model or equation that represents the relationship between the number of people and the cost. In this case, the linear model will be in the form of y = mx + b, where y represents the cost and x represents the number of people.

To obtain the slope, m, we can choose any two points from the table and use the formula:
slope (m) = (change in y) / (change in x)

Let's choose the points (10, $200) and (14, $252):
change in y = $252 - $200 = $52
change in x = 14 - 10 = 4

So, the slope (m) will be:
m = $52 / 4 = $13

Now that we have the slope, we can find the y-intercept, b, by substituting the values of one of the points into the equation:
$200 = $13(10) + b

Simplifying:
$200 = $130 + b
b = $200 - $130
b = $70

Therefore, the linear equation that represents the relationship between the number of people and the cost is:
y = $13x + $70

Now, we can use this equation to find the approximate residual value for feeding 21 people. Substituting x=21 into the equation, we get:
y = $13(21) + $70
y = $273 + $70
y = $343

Therefore, the approximate residual value for feeding 21 people is $343.

Looking at the answer choices provided, we find that none of them match the result we calculated. It is possible that there was an error in either your calculations or the answer choices. I recommend double-checking your work and calculations to ensure accuracy.