Question 140700
Let's assigned "x"= child's plate and "y"=adult's plate.
So, x+y=250 right? (assuming all the 250plates were used)
Mark this equation 1.
Then when we multiply the child's plate "x" by $3.50) + (adult's plate "y" times $7.00)equals $1347.50. To show,
{{{3.50(x)+$7.00(y)}}}=$1347.50. Mark this equation 2.
In equation 1 we get {{{y=250-x}}}, then substitute this "y" value in equation 2.
Therefore,
{{{3.50(x)+$7.00(250-x)}}}=$1347.50
{{{3.50(x)+1750.50-7.00x=1347.50}}}
{{{3.50x=402.50}}}
{{{x=115}}}, this is # of child's plate
For adult, go back equation 1, y=250-115
{{{y=135}}}, # of adult's plate
In doubt? Simply check and go back equation 2,
{{{3.50(115)+7.00(135)=1347.50}}}
{{{402.50+945=1347.50}}}
$1347.50=$1347.50
</pre><font size=4><b>Thank you,
Jojo</pre>