We know that the skid marks (d)= 150 feet.
S= speed in miles per hour (what we have to figure out)
0.75*150=112.5 (left side is now figured out)
Now we have to figure out s^2/30.25
Let's multiply both sides by 30.25
Square root of 3402.125=58.3277378
So our answer is about 58 miles per hour.