737 miles per 11 hours
737:11 is the ratio of distance to time
so the other ratio we have is
603:x, x is missing
we assume the ratios to be equal so
737:11=603:x
fractionify
737/11=603/x
multiply both sides by 11x
737x=6633
divide both sides by 737
x=9
answer is 9 houurs