Hint
This question all comes down to recognizing that the system, $y_{ n+1} = 0.3 y_n$, means that you multiply by $0.3$ to go from one time step to the next. To advance one time step (i.e., go from $x_0$ to $x_1$, or from $x_1$ to $x_2$, or from $x_7$ to $x_8$), you multiply by $0.3$ one time. Repeat the procedure to advance more than one time step.
Presumably, you will use your calculator to get these numbers. Be sure, though, to keep lots of digits. We require you keep 6 digits, but it's always a good idea to enter at least one more digit that we require to be one the safe side. So, if your calculator says something like 6.866455078125E-05 or 6.866455078125 × 10-5, then go ahead and enter a number such as 6.8664551E-05 for your answer.
One last thing: don't round numbers in the middle of your calculations. Just keep all the digits your calculator has (for example by storing values in your calculator memory or recalling the previous answer and building on it). If you round numbers from the middle of your calculations to 6 digits, the end result might be accurate to only 5 digits, given the way rounding errors can accumulate.
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