Step 1 :Given that the speed \(R\) varies inversely with the time \(T\), we can express this relationship as \(R = \frac{k}{T}\), where \(k\) is the constant of variation.
Step 2 :Given that \(R = 56\) mph when \(T = 9\) seconds, we can find the constant of variation \(k\) by multiplying these values. So, \(k = R \times T = 56 \times 9 = 504\).
Step 3 :We are asked to find the speed of a car that travels the given distance in 7 seconds. We can find this by substituting \(T = 7\) seconds and \(k = 504\) into the equation \(R = \frac{k}{T}\). So, \(R = \frac{504}{7} = 72\) mph.
Step 4 :Final Answer: The speed of a car that travels the given distance in 7 seconds is \(\boxed{72}\) mph.