Explanation: The general formula for nth term in a geometric sequence is an=a1*r^(n-1), where a1 is the first term, r is the common ratio, and n is the position in the term (in this case 14).
To find the common ratio, we can simply divide the next term after the first (20/2=10).
So, an=10*2^(14-1).
After doing the parentheses and multiplication, we have 20^13, which is 81920.
