Ratios and Rates

Chapter 5 Lesson 1

Ratio

Compares two numbers using division. EX) 2/5


To write a ratio as a fraction simply put the first number in the numerator and the second in the denominator. Simplify if necessary.


Ex - 8 to 16


8/16 = 1/2


Ex - 3 to 5


3/5

Rate

A ratio of two numbers with different units. EX) 180 miles/ 2 hours, 4 inches/ 2 years.


To write a rate as a fraction in simplest form...


Example - 16 dogs to 12 cats

1.Write as fraction


  • 16 dogs / 12 cats


2. Simplify, in this case divide numerator and denominator by


  • 4 dogs / 3 cats



Example - 45 males and 60 females

1. Write as fraction


  • 45 males / 60 females


2. Simplify, in this case divide numerator and denominator by 15


  • 3 males / 4 females

Unit Rate

A rate with a denominator of one. EX) 30 miles/1 hour 43 words/1 minute $3.46/1 pound


When finding a unit rate your final answer should always have a denominator of one.


Example - 2.5 miles in 5 minutes


1. Write as fraction



  • 2.5 miles / 5 min


2. Divide numerator and denominator by denominator so that the denominator is 1 in this case we divide by 5.




  • 0.5 miles / 1 minute



Example - 342 words in 6 minutes

1. Write as fraction



  • 342 words / 6 minutes


2. Divide numerator and denominator by denominator so that denominator is 1, in this case we divide by 6.




  • 57 words / 1 minute