10. Police can estimate the speed of a car by the length of the skid marks made when the
driver braked. The formula is v=√√30df. In this formula, v is the speed in miles per
hour, d is the length of the skid marks, in feet, and f is the coefficient of friction. What
was the speed of a vehicle if the skid marks were 75ft long and the coefficient of friction
was 0.7? Do not use a calculator for this question, show your work by using prime
factorization and leave your final answer in mixed radical. [2]
