Question

a gallon of gasoline cost $3.09 two years ago. Now it costs $1.78. To the nearest percent, what has been the annual rate of decrease in cost?

Answer 1

Given that a gasoline was $3.09  two years ago and it goes for $1.78 now, the rate of decrease will be:
(Δ prices)/(time taken)
=(1.78-3.09)/2
=-1.31/2
=-.655 dollars per year.
the answer is -0.655 dollars per year