We can calculate the speed to be
.. (36 mi)(0.75 h) = 48 mi/h
or we can just assume that is what it is based on the fact that 48 is the only number in any of the offered answers.
distance = speed * time
.. y = 48 * x . . . . . . . . . . . . . . . . corresponds to selection A
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There is no question 17.
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15. All sections of the graph are linear. All sections except Q show the function increasing (left to right, which is how we talk about it). Thus selection B is the only sensible one.