In a village the cases of a particular infectious disease have been exponentially decreasing at a rate of 90% per year since the people started recieving the vaccine. If there were 100 cases to start with. Predict the number of cases after 2 years.

Which expressions are equivalent to k/2 choose 2 answers: a k-2 b 2/k c 1/2k d k/2 e k+k

Sanya noticed that the temperature was falling at a steady rate of 1.4 degrees every hour from the time that she first checked her outdoor thermometer. by 6 a.m., the temperature had fallen 21 degrees. which expression can you use to find how many hours earlier she had first checked the thermometer?

Starting at home, emily traveled uphill to the hardware store for 606060 minutes at just 666 mph. she then traveled back home along the same path downhill at a speed of 121212 mph. what is her average speed for the entire trip from home to the hardware store and back?