standard_description: Understand solving an equation or inequality as a process of answering a question: which values from a specified set, if any, make the equation or inequality true? Use substitution to determine whether a given number in a specified set makes an equation or inequality true.
problem_activity: Task
2 bottles of water cost $5.00.
Fill in the table that shows the costs for 4, 6, and 8 bottles. Find the cost for a single bottle in each case.
{"table": [{"thead": [{"tr": [{"th": [{"_attributes": {"scope": "col"}, "_value": "Number of bottles"}, {"_attributes": {"scope": "col"}, "_value": "Cost (\\$)"}, {"_attributes": {"scope": "col"}, "_value": "Cost per bottle"}]}]}], "tbody": [{"tr": [{"td": [{"_value": "$$2$$"}, {"_value": "$$5$$"}, {}]}, {"td": [{"_value": "$$4$$"}, {}, {}]}, {"td": [{"_value": "$$6$$"}, {}, {}]}, {"td": [{"_value": "$$8$$"}, {}, {}]}]}]}]}
5 granola bars cost $4.00
Fill in the table that shows the costs for 10, 15, and 20 granola bars. Find the cost for a single granola bar in each case.
{"table": [{"thead": [{"tr": [{"th": [{"_attributes": {"scope": "col"}, "_value": "Number of granola bars"}, {"_attributes": {"scope": "col"}, "_value": "Cost (\\$)"}, {"_attributes": {"scope": "col"}, "_value": "Cost per bar"}]}]}], "tbody": [{"tr": [{"td": [{"_value": "$$5$$"}, {"_value": "$$4$$"}, {}]}, {"td": [{"_value": "$$10$$"}, {}, {}]}, {"td": [{"_value": "$$15$$"}, {}, {}]}, {"td": [{"_value": "$$20$$"}, {}, {}]}]}]}]}
Explain why if you can buy $a$ items for $b$ dollars, or buy $2a$ items for $2b$ dollars, the cost per item is the same in either case.


aligns: no