Question

hala can ride her bike 7 1/2 miles in an hour, How far will she ride in 3 hours? how fat will she ride in 1/3 of an hour?

Answer 1

In 3 hours she will ride 22 1/2 miles. And in 1/3 of an hour she will ride 2 1/2 miles. 

Explanation: Since you already know how much she can ride in one hour, but you need to know three hours, you multiply how many miles she can bike in one hour by three. 
7 1/2 x 3 = 15/2 x 1/3 = 45/2 = 22 1/2

Then to find how much she can bike in 1/3 of an hour, you multiply 7 1/2, the amount of one hour, by 1/3, the amount of time. 
7 1/2 x 1/3 = 15/2 x 1/3 = 15/6= 2 3/6 = 2 1/2 

(And in case you don't know how to multiply fractions, whole, and mixed numbers then here: make all numbers into fractions [both proper and improper], and then just multiply across or cross cancel if possible. Simplify if necessary.)