Question

In the sequence 1, 2, 4, .... an an , every nth term for n > 1 is created by the equation an=a(n?1)?2 an=a(n?1)?2 . by what percent is the 11th term greater than the 9th term in this sequence?

Answer 1

Each term is doubled
the equation is $a_n=a_1(2)^{n-1}$ where an=nth term
a1=first term
n=which term

ok

so if the 9th term is x then the 10th term is 2x then 11th is 4x
so how much larger is the 11th term than the 9th term?
4x vs x
it's 4 times bigger or 400%