Answer:
Average Loss per year = 50000 African Elephants.
Step-by-step explanation:
Remark
Usually these problems are compounded, but I don't think this one is. I think you are just asked to give the annual decline. If you are taking up exponential formulas, please leave a note, because my answer will be incorrect. If you have no idea about what I've written, then just type in my answer and see what happens.
Givens
t = 2000 - 1930 = 70 years.
Elephant difference = 4000000 - 500000 = 3,500,000
Formula
Average loss per year = total elephant Loss/ # years
Solution
Average = 3500000/70
Average = 50,000
Comment
I think the average loss per year speaks for itself. It means that those elephants that were born could not make up for those that were lost to natural causes and hunting for tusks. Every year the net loss was 50000