Ageometric sequence is shown on the graph below. what is the formula for the nth term of the sequence?

Remember, an=a1(r)^(n-1) where a1=first term or where n=1 and r=commmon ratio a2/a1=r so if you have the graph, find the y value coresponding to x=1 and that is a1 find the y value coresponding to x=2 and taht is a2, do a2/a1 to get r

so like I was saying

well, each term is 1/2 of the previous
20/40=1/2
so r=1/2
and a1=40
so
is da equation

The correct answer is c