Question

Selma uses a jogging trail that runs through a park near her home. The trail is a loop that is of a mile long. On Monday, Selma ran the loop in of an hour. What is Selma’s unit rate in miles per hour for Monday’s run?

In this activity, you will use the common denominator method to calculate a unit rate that involves fractions. Answer the questions that follow to calculate Selma’s unit rate in miles per hour.


part A. According to the question, the unit rate is to be expressed in which units?


Part B. Now, write Selma’s jogging rate as a complex fraction. A complex fraction is one whose numerator, denominator, or both are fractions. Be sure to include units in your answer.


Part C. Find the least common denominator of the two fractions from part B. To do this, list and compare the first five multiples of the denominators. The smallest number that appears in both lists is the least common denominator. Show your work.


Part D

Answer 1

a) Her rate is 1 mile per hour for Monday’s run

b) 0.447 m/second

c) In fraction 20467m/180000 seconds

Explanation:

Speed = distance / time = 1 mile/ 1 hour

= 1 mile per hour

Her rate is 1 mile per hour for Monday’s run

part A. According to the question, the unit rate is to be expressed in miles per hour units.

Part B.

Speed = distance / time = 1 mile/ 1 hour

= 1 mile per hour

But 1 mile = 1609.34 m

and 1 hour = 3600 seconds

There fore

1 mile/ 1 hour = 1*1609.34/ 1*3600 seconds

= 0.447 m/second

Part C.

1 mile/ 1 hour =1609.34/ 3600 seconds

= 1609.34 * 100/100 * 1/3600 ( multiplying and dividing by 100 to remove the decimal)

= 160934/360000

= 20467m/180000 seconds

The first five multiples of 1 are 2,3,4,5,6,7,8, 9......

The LCM of 1 and 1 is 1