A Father Walks 36 Miles In 12 Hours While His Son Covers The Same Distance On A Bicycle At Twice The Father's Rate Of Speed. At This Rate, How Many Miles Would The Bicycle Rider Travel In 9 Hours?

In one hour his father would travel 3miles(Divide both sides of 36/12 by 12)
so his son is double of that speed which would be 6miles per hour
so after 9hours, his son would travel 6milesx9hours which is equal to 54miles