4/10= 8/20, 2/5. For 8/20 u multiply 2 times and for 2/5 u divide by 2
Hope that helps u
So 55% is really 55/100
You take 100 - 55 to find how much Mr. Williams drove
100 - 55 = 45
So Mr. Williams drove 45/100 of the miles
Simplified is 9/20 of the miles
y = 3/2x is the answer for this problem.