6. The value of a particular used car has been decreasing at the same rate each year since \( 2010 \) . The equation \( C ( t ) = 25,000 \cdot ( 0.78 ) ^ { t } \) represents the value of the car \( C ( t ) \) , in dollars, as a function of \( t \) , the number of years since \( 2010 \) .
a. What do the numbers \( 25,000 \) and \( 0.78 \) tell us about this situation?
b. What is the percent decrease of the value of the car each year?
c. Sketch a graph of \( C \) .