# Math Help - Linear equation

1. ## Linear equation

Hello Friends,
I wonder if anybody helps me to solve this mathematic sum.. I solved it a bit but I could not sum it up .. here is the question

If the number of children attending the party is represented by x, explain in words why the linear equations y =9x +50 (for Playzone),
y
=4x + 100 (for Kidzville) can be used to give the total cost y (in pounds) for each venue.

sol. y=9x + 50
y=4x + 100
after solving it we get
x = 10

Now I am bit confused about how to explain in words these why the linear equations can be used to give total cost y in each venue...
May be its very simple but I am too thick to get it..
plz help me out..
Thanks

2. Originally Posted by nataliesingh
Hello Friends,
I wonder if anybody helps me to solve this mathematic sum.. I solved it a bit but I could not sum it up .. here is the question

If the number of children attending the party is represented by x, explain in words why the linear equations y =9x +50 (for Playzone),
y
=4x + 100 (for Kidzville) can be used to give the total cost y (in pounds) for each venue.

sol. y=9x + 50
y=4x + 100
after solving it we get
x = 10

Now I am bit confused about how to explain in words these why the linear equations can be used to give total cost y in each venue...
May be its very simple but I am too thick to get it..
plz help me out..
Thanks
Now substitute $x = 10$ into either equation to find $y$.

3. Originally Posted by Prove It
Now substitute $x = 10$ into either equation to find $y$.
hi,
thanks for replying..i did that bit as well..
y= 9x10+50 (x=10)
y= 140
then.
y= 4x10+100
y= 140
so I did it but still confused how to explain in words that why the linear equations can be used to give the total cost y (in pounds) for each venue.

thanks

4. Originally Posted by nataliesingh
hi,
thanks for replying..i did that bit as well..
y= 9x10+50 (x=10)
y= 140
then.
y= 4x10+100
y= 140
so I did it but still confused how to explain in words that why the linear equations can be used to give the total cost y (in pounds) for each venue.

thanks

hi,
its quite strange that my post has 36 views but got only one reply...seems like no mathematician around here...I dont think this sum is so difficult to solve...
cheers..

5. Equation 1:

$50 starting cost and$9 per person, if $y$ is the cost and $x$ is the number of people, then

$y = 9x + 50$.

Equation 2:

$100 starting cost and$4 per person, if $y$ is the cost and $x$ is the number of people, then

$y = 4x + 100$.