Solving using equations

[Cindy Burgess]

I am having trouble answering this homework question, please help:

Ronald is setting up an aquarium in his new office. At one pet store, fish cost $2 each and an aquarium cost $40. At another pet store, fish cost $3 each and an aquarium cost $36. Write and solve a system of equations to represent the cost of x fish and an aquarium at each store. Solve this using the system. What does this solution represent? If Ronald wants 5 fish, from which pet store should he buy his aquarium? Explain

 

[Deleted member 4993]

I am having trouble answering this homework question, please help:

Ronald is setting up an aquarium in his new office. At one pet store, fish cost $2 each and an aquarium cost $40. At another pet store, fish cost $3 each and an aquarium cost $36. Write and solve a system of equations to represent the cost of x fish and an aquarium at each store. Solve this using the system. What does this solution represent? If Ronald wants 5 fish, from which pet store should he buy his aquarium? Explain

x = # of fish

Cost at pet store #1 → x * 2 + 40

continue....

Please share your work with us.

You need to read the rules of this forum. Please read the post titled "Read before Posting" at the following URL:

http://www.freemathhelp.com/forum/th...217#post322217

We can help - we only help after you have shown your work - or ask a specific question (e.g. "are these correct?")

 

[Cindy Burgess]

Here is my work

$2 = fish Aquarium = $40
$3 = fish Aquarium = $36

Store 1 2x + y= 40 y = 40 - 2x 40 - 2x = 36 - 3x x = -4 y= 48
Store 2 3x + y = 36 y = 36 - 3x y =48


This is one way I worked it.

This is the other way I tried.

2x + 40 = y 2x + 40 = 3x + 36 X=4 y=48
3x + 36 = y y=48

It appears that purchasing 5 fish would be cheaper at Store 1 and the aquarium would be cheaper at Store 2.

 

[HallsofIvy]

It's impossible to say whether that is right or wrong because you haven't said what "x" and "y" represent. I might assume that "x" is the number of fish bought, just because Subhotosh Khan said that. But what does "y" represent? And I don't see how the cost of fish plus some number should equal to the cost of the aquarium. Have you tried setting it up the way Subhotosh Khan suggested?

(This is not really a "system" of equations, it is two separate equations with "x" representing different things in each equation.)

 

[Cindy Burgess]

x does equal the number of fish. I was letting y = the total cost of purchase based on setting the equations equal to each other. Is this correct?

 

[Deleted member 4993]

x does equal the number of fish. I was letting y = the total cost of purchase based on setting the equations equal to each other. Is this correct?

No... There is nothing in the problem statement (that you posted) to suggest the cost of total purchases should be equal.