Marley’s cup of tea was cooling. Its temperature with relation to time can approximately be modeled by the function $f(t)=140(0.5)^t+72$.

1. What does the $72$ represent in this situation?

   Hint (a):

   As t gets larger, the function value approaches 72.

   More Help:

   Consider the significance of part b. Will the tea get cooler than surrounding air temperature?

2. Marley decides to save energy and lower the temperature of her cottage to $68º$. How would this change the model?

• Answer (b)

  $f(t)=140(0.5)t+68$