You have $E[x]= 3.5$ and $ \sigma_x^2 \approx 3 $. Then $E[Z]= 42$ , $ \sigma_Z^2 \approx 36 $, $ \sigma_Z \approx 6 $
By Chebyshev's inequality (one sided) $$P(Z<30) \approx P(\mu -Z \ge 12 ) = P(\mu -Z \ge 2 \sigma_Z) \le \frac12 \frac14 = \frac18$$
This is non conclusive (you want $P(Z<30)>\frac{1}{10}$ to play the game), but knowing that the Chebyshev's inequality is very loose, you should not play.
