Answer:
The score is [tex]x = 1884[/tex]
Step-by-step explanation:
From the question we are told that
The population mean is [tex]\mu = 1500[/tex]
The standard deviation is [tex]\sigma = 300[/tex]
From the question we are told that the score follow a normal distribution
i.e [tex]X \~ \ N( 1500 , 300)[/tex]
The proportion of score in the top 10% is mathematically
[tex]P(X > x ) = P( \frac{X - \mu}{\sigma } > \frac{x - \mu}{\sigma } ) = 0.10[/tex]
Where x is the minimum score required to be in the top 10%
Now the [tex]\frac{X - \mu}{\sigma } = Z (The \ Standardized \ value \ of \ X)[/tex]
So
[tex]P(X > x ) = P( Z > \frac{x - \mu}{\sigma } ) = 0.10[/tex]
So
[tex]P(X > x ) = P( Z > \frac{x - 1500}{300} ) = 0.10[/tex]
So the critical value of 0.10 from the normal distribution table is [tex]Z_{0.10} = 1.28[/tex]
So
[tex]\frac{x - 1500}{300} = 1.28[/tex]
[tex]x = 1884[/tex]