Question

The ages of visitors to a theme park are normally distributed with a mean of 15 years and a standard deviation of 5.2 years. Approximately 70% of the visitors to the theme park are older than which age?

A.11.4
B. 12.3
C. 17.7
D. 18.6

Answer 1

Answer: The correct answer is Choice B, 12.3 years.

A z-score of about -0.523 would corresponding to the area which divides the normal distribution at 70% and 30%.

Now, we just need to write and solve an equation for that z-score.

(x - 15) / 5.2 = -0.523
x - 15 = -2.7196
x = 12.283

We can round it to 12.3 years old.