Question

Mike forgot to replace the cap on a bottle of room freshener. The room freshener began to evaporate at the rate of 15% per day. If the original amount of room freshener in the bottle was 40 grams, which of the following graphs best represents the amount of room freshener f(x) that would remain in the bottle after x days?
graph of function f of x equals 30 multiplied by 0.88 to the power of x

graph of exponential function going down from left to right in quadrant 1 through the point 0, 40 and approaching the x axis

graph of function f of x equals 50 multiplied by 0.82 to the power of x

graph of exponential function going down from left to right in quadrant 1 through the point 0, 4 and approaching the x axis

Answer 1

The decay rate is 100% - 15% = 75% = 0.75

The decay equation is f(x) = 40(0.75)ˣ
Where f(x) is the mass of air freshener left after x days of use

The graph of this function is given below 

The correct description of the graph is statement 2:

graph of exponential function going down from left to right in quadrant 1 through the point 0, 40 and approaching the x axis