document.write( "Question 140997: The director of a summer day cmp estimates that 100 children will join if the camp fee is 250.00, but for each 20.00 decrease in the fee, ten more children will enroll.
\n" ); document.write( "Determine the linear equation tha will represent the number of children who will enroll a a given fee.\r
\n" ); document.write( "\n" ); document.write( "Graph the linear equatin that rpresens the number of children who will enroll at a given fee.\r
\n" ); document.write( "\n" ); document.write( "How many students will enroll if the camp fee is 180.00?\r
\n" ); document.write( "\n" ); document.write( "How many studens will enroll if the camp is free?
\n" ); document.write( "

Algebra.Com's Answer #102665 by ankor@dixie-net.com(22740)\"\" \"About 
You can put this solution on YOUR website!
The director of a summer day camp estimates that 100 children will join if the camp fee is 250.00, but for each 20.00 decrease in the fee, ten more children will enroll.
\n" ); document.write( "Determine the linear equation that will represent the number of children who will enroll a a given fee.
\n" ); document.write( ":
\n" ); document.write( "Let x = cost per child
\n" ); document.write( "Let y = no. of children enrolled
\n" ); document.write( ":
\n" ); document.write( "From the information given, derive two set of x/y coordinates
\n" ); document.write( "100 kid at $250: x1=250, y1=100
\n" ); document.write( "and
\n" ); document.write( "110 kids at $230: x2=230, y2=110
\n" ); document.write( ":
\n" ); document.write( "Find the slope using the slope equation: m = \"%28y2-y1%29%2F%28x2-x1%29\"
\n" ); document.write( "m = \"%28110-100%29%2F%28230-250%29\" = \"10%2F%28-20%29\"
\n" ); document.write( "m = \"-1%2F2\"
\n" ); document.write( ":
\n" ); document.write( "Use the point/slope equation: y -y1 = m(x-x1)
\n" ); document.write( ":
\n" ); document.write( "y - 100 = \"-1%2F2\"(x - 250)
\n" ); document.write( "y - 100 = \"-1%2F2\"x + 125
\n" ); document.write( "y = \"-1%2F2\"x + 125 + 100
\n" ); document.write( "y = \"-1%2F2\"x + 225; is the linear equation
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "Graph the linear equation that represents the number of children who will enroll at a given fee.
\n" ); document.write( ":
\n" ); document.write( "Graph y = \"-1%2F2\"x + 225,
\n" ); document.write( "To graph this, use an x scale of 0 to +450, and y scale from 0 to 300
\n" ); document.write( "(we are not interested in any neg values here)\r
\n" ); document.write( "\n" ); document.write( "You only need two pair of coordinates to plot a linear (straight line) graph
\n" ); document.write( "However here are three sets: we will find y for x = 100, x = 200, x = 250
\n" ); document.write( ":
\n" ); document.write( "Substitute 100 for x, in the equation y = -.5x + 225 and find y
\n" ); document.write( "y = -.5(100) + 225
\n" ); document.write( "y = -50 + 225
\n" ); document.write( "y = +175
\n" ); document.write( ":
\n" ); document.write( "If we were making a table for x/y values, it would be:
\n" ); document.write( " x | y
\n" ); document.write( "-------
\n" ); document.write( "100|175
\n" ); document.write( ":
\n" ); document.write( "Substitute 200 for x and find y:
\n" ); document.write( "y = -.5(200) + 225
\n" ); document.write( "y = -100 + 225
\n" ); document.write( "y = +125
\n" ); document.write( "now our table is:
\n" ); document.write( " x | y
\n" ); document.write( "-------
\n" ); document.write( "100|175
\n" ); document.write( "200|125
\n" ); document.write( ":
\n" ); document.write( "Substitute 250 for x, find y
\n" ); document.write( "y = -.5(250) + 225
\n" ); document.write( "y = -125 + 225
\n" ); document.write( "y = +100
\n" ); document.write( "we have:
\n" ); document.write( "x | y
\n" ); document.write( "-------
\n" ); document.write( "100|175
\n" ); document.write( "200|125
\n" ); document.write( "250|100
\n" ); document.write( " 0 |225, note this is the y intercept (the camp is free, 225 kids)
\n" ); document.write( ":
\n" ); document.write( "Plot these 4 points, join them with straight lines
\n" ); document.write( ":
\n" ); document.write( "it should look like this:
\n" ); document.write( "\"+graph%28+300%2C+200%2C+-50%2C+450%2C+-50%2C+275%2C+-.5x%2B225%29+\"
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "How many students will enroll if the camp fee is 180.00?
\n" ); document.write( ":
\n" ); document.write( "substitute 180 for x in our equation and find y
\n" ); document.write( "y = \"-1%2F2\"(180) + 225
\n" ); document.write( "6 = -90 + 225
\n" ); document.write( "y = +135 will enroll
\n" ); document.write( ";
\n" ); document.write( ":
\n" ); document.write( "How many students will enroll if the camp is free?
\n" ); document.write( ":
\n" ); document.write( "In this case x = 0
\n" ); document.write( "y = \"-1%2F2\"(0) + 225
\n" ); document.write( "y = 225 enrolled if it is free, you can see on the graph, that's the y intercept
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "did this make sense to you, any questions?
\n" ); document.write( "
\n" );