To find the probability that a car is traveling at more than 100 km/hr, we need to calculate the z-score for 100 km/hr using the provided mean and standard deviation.
The formula for the z-score is: \[ z = \frac{(X - \mu)}{\sigma} \] where:
- \(X\) is the value we are examining (100 km/hr),
- \(\mu\) is the mean (90 km/hr), and
- \(\sigma\) is the standard deviation (10 km/hr).
Substituting the values in: \[ z = \frac{(100 - 90)}{10} = \frac{10}{10} = 1 \]
Next, we look up the z-score of 1 in the standard normal distribution table to find the probability of a car traveling less than 100 km/hr. The table shows:
\[ P(Z < 1) \approx 0.8413 \]
To find the probability of a car traveling more than 100 km/hr, we need to subtract this from 1:
\[ P(X > 100) = 1 - P(Z < 1) = 1 - 0.8413 = 0.1587 \]
Therefore, the probability that a car picked at random is traveling at more than 100 km/hr is approximately:
\[ \boxed{0.159} \]
when rounded to the nearest thousandth.