What is the maximum safe​ speed?

Question

The formula v= √2.5r models the safe maximum​ speed, v, in miles per​ hour, at which a car can travel on a curved road with radius of​ curvature, r, in feet. A highway crew measures the radius of curvature at an exit ramp as 1,000 feet.

Answer 1

I assume that the question is "What is the maximum safe speed that a car can travel on the exit ramp?" The key here is to get your units right. The formula is in miles/hour but the radius is in feet. So you need to convert the 1000 feet to miles:

radius (in miles) = radius (in feet) x (1/5280 miles/feet)

Then just plug the radius value in miles into the formula and use your calculator to get an answer.