D .............................
The equation is a scientific law, Newton's Law of Gravity,
This is a pretty bad question. Newton's Law of Gravity is a mathematical model of gravitation, originally a theory, verified by observation, and now superseded by the General Theory of Relativity.
C is probably the best answer to this poor question.
This is hard in mathematical language, but there is only this way to present it. Let us denote by A the consentration of the substance and by A' its rate.
We have that b/A= t+c where c is a constant.
Hence A=b/(c+t)
By differentiating, we get that A'=-b/(C+t)^2
Then, we have that -(A)^2=A'/b
Hence at any point, we have that if we make the concentration 17 times, we have that there is a 17 times bigger , the rate will become bigger by 17*17, hence 289 times faster.
48 miles/4hrs = 12 mph
Increased Speed 12 mph + 8mph = 20 mph
Distance left 108 miles - 48 miles = 60 miles
Time left 60 miles/20 mph = 3 hours
