Question

Mrs. Santos is buying binders for the students in her class. She determined that 15 binders would cost $22.50.

Answer 1

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Mrs. Santos is buying binders for the students in her class. She determined that 15 binders would cost $22.50.

Cost of Binders
On a coordinate plane, a graph titled Cost of Binders has number of binders on the x-axis and total cost in dollars on the y-axis. The line goes through points (0, 0) and (15, 22.5).

If all of the binders cost the same amount, which statement is true?
It will cost $12 for 18 binders.
It will cost $20 for 30 binders.
It will cost $42 for 28 binders.
It will cost $48 for 48 binders.

Answer 2

you could use the graph to try and match up the appropriate cost with the # of binders (for example, looking at the graph, does $12 match up with 18 binders? if not, move to the next answer choice, etc.)

you could also calculate the cost per binder by dividing ($22.50 / 15 binders). from there, you can test each answer choice by multiplying (cost per binder) * # of binders and see if it matches the answer choice