Answer:
475.
Step-by-step explanation:
We have been given that for a normal distribution with μ=500 and σ=100. We are asked to find the minimum score that is necessary to be in the top 60% of the distribution.
We will use z-score formula and normal distribution table to solve our given problem.
Top 60% means greater than 40%.
Let us find z-score corresponding to normal score to 40% or 0.40.
Using normal distribution table, we got a z-score of .
Upon substituting our given values in z-score formula, we will get:
Therefore, the minimum score necessary to be in the top 60% of the distribution is 475.