Using the Definition of average speed, we have:

Obs: approximate results
Letter DIf you notice any mistake in English, please let me know, because I'm not native.
the answer is A :)))))))))))))))))
1.75 because you would divide 3.5 by 2
Solution:
1)Distance covered by cyclist=3.75 miles.
Time =0.3 hours.
Speed= Distance ÷Time
Speed =3.75÷0.3=12.5 miles per hour.
2) Speed = 12.5 miles per hour, Distance = 4.5 miles .
Time = Distance ÷Speed.
Time = 4.5÷12.5=0.36 hours.
Time taken to cover 4.5 miles is 0.36 hours.
In this equation, y = mx + b where m is the slope. So on 17, the slope is -5. On 18, the slope is 1/3.