Aquarium You want to set up an aquarium and need to determine what size tank to buy. The graph shows tank sizes using a rule that relates the capacity of the tank to the combined lengths of the fish it can hold.
If you want five 2-in. platys, four 1-in. guppies, and a 3-in. loach, which is the smallest capacity tank you can buy: 15-gallon, 20-gallon, or 25-gallon? Use a table to find the answer.
How can you use the given graph?
You can use the graph to make a table and find a pattern relating capacity and combined fish length.
Think | Write | ||||||||||||
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Choose some points on the graph. | (0, 2), (5, 7), (10, 12) | ||||||||||||
Make a table using the input and output values shown in the ordered pairs. Find a pattern in the process column. Each output is 2 more than the corresponding input. |
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You want 5 platys, 4 guppies, and 1 loach. So, you will have a total of 17 in. of fish. Find the output when the input is 17. |
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Write the answer in words. | You need to buy the 20-gal tank. |