Answer:
[tex]\text{ \$685.25}[/tex]Explanation:
Here, we want to get the amount of money that would guarantee that a person has more money than 80%
That means the probability is greater than 80% or 0.8
Thus, we need to get the z-score that corresponds to this probability
Using a z-score table, we can get this as follows:
[tex]P(x\text{ }>\text{z\rparen= 0.842}[/tex]We will now get the value from the obtained z-score
Mathematically:
[tex]\begin{gathered} z\text{ = }\frac{x-\mu}{\sigma} \\ \\ \text{ x is the value we want to calculate} \\ \mu\text{ is the mean} \\ \sigma\text{ is the standard deviation} \end{gathered}[/tex]Substituting the values, we have it that:
[tex]\begin{gathered} 0.842\text{ = }\frac{x-580}{125} \\ \\ \text{ x = 580 + 125\lparen0.842\rparen} \\ x\text{ = \$685.25} \end{gathered}[/tex]