1. **State the problem:** We need to find the total probability that a visitor's first ride is either the spinning teacups or the roller coaster, given as 20% + 0.34. 2. **Convert percentage to decimal:** 20% means 20 out of 100, so as a decimal it is $\frac{20}{100} = 0.20$. 3. **Add the probabilities:** Now add the decimal 0.20 and 0.34. $$0.20 + 0.34 = 0.54$$ 4. **Interpretation:** The total probability as a decimal is 0.54, meaning there is a 54% chance the visitor's first ride is either the spinning teacups or the roller coaster. **Final answer:** $$\boxed{0.54}$$