35. The expression \( \sqrt { 30 f s } \) gives the speed in miles per hour of a vehicle that makes a skid mark \( s \) feet long on a road with a coefficient of friction \( f \) . How fast was the going if its skid mark was

\( 75 \) feet long and then coefficient of friction is \( .90 \) ? A. \( 75 \) miles per hour B. \( 52 \) miles per hour C. \( 45 \) miles per hour D. \( 10 \) miles per hour