Wow this math got out of hand quickly, for fun I send this to my cousin who is a math professor at Rice University, she said:
"I can't believe this, it's overly simple. 2x=(360/4) solve for "x"
Work within the parenthesis first, (360/4)=90. Period! 360 divided by 4 is 90!
So, 2x=90. Divide both sides by 2, so X=45. The speed limit is 45"
CP looks like you were doing extra math, you were doing 3x60 divided by 4 when it was just 360 divided by 4