Unit Rates
B. Unit Rates
A unit rate is a rate where the value of the second term is 1. A unit rate can be thought of as a value per single unit of measurement, such as 60 km/1 hour (60 km/h), $2.99/1 kg ($2.99/kg), etc. It is common for a rate to be expressed as a unit rate.
Example 1
A 15-ounce bottle of shampoo sells for $6.49. Find the unit price.
Let p = unit price and let the unit of measure = 1 ounce.
The unit price is approximately $0.43/ounce.
Example 2
In April of 2009, the flu pandemic H1N1 spread across many countries, infecting the human population in each. By its post-pandemic phase (May 2010), it had killed 18 000 people. Determine the average number of deaths per month and per day.
Per month:
There were 13 months from April 2009 to May 2010 and in that time, 18 000 people died.
An average of 1385 people/month died between April 2009 and May 2010 because of H1N1.
Per day:
There were 396 days from April 2009 to May 2010 and in that time, 18 000 people died.
An average of 45 people/day died between April 2009 and May 2010 because of H1N1.