Here's my question:

The answer to this probelm is:

$\displaystyle

S_{n} = 0.076 S_{n-1}

$

I don't see how to get this answer, here's my attempt:

Equation has to be of the form $\displaystyle S_{n} = k S_{n-1}$, where k is some constant. I don't understand how they've got k=0.076

Any explanation would be helpful.