Miles math equation

Question

In 1 3/4 hour Sarah walks 6 1/2 miles. At this rate, how many miles can she walk in one hour?

Answer 1

The problem is asking you to find what's called a "unit rate."  That is, how many of these do we have for one of those?"  In this problem, it is, "How many miles for one hour?"

 

So, divide miles by hours (that is miles/hour) to "get miles per hour."

 

     6 1/2 miles  per  1 1/4 hours

       13/2 miles per 7/4 hour             [convert mixed numbers to improper fractions --

                           it is important to learn the terms while you are doing this]

       (13/2 miles) / (7/4 hour)                ["per" means "/"]

       (13/2)*(4/7)  miles/hour              [note: to divide by fraction, invert and multiply]

        (26/7) miles/hour

          3 5/7 miles/hour                 [convert improper fraction back to mixed number]

 

Note: Since this problem uses mixed numbers, there us no reason to introduce decimal notation.

Answer 2

6.5 / 1.75 = (13/2) / (7/4) = 13/2 x 4/7 = 52/14 = 3.714 m/hr