Answer:
The amount of money separating the lowest 80% of the amount invested from the highest 20% in a sampling distribution of 10 of the family's real estate holdings is $238,281.57.
Step-by-step explanation:
Let the random variable <em>X</em> represent the amount of money that the family has invested in different real estate properties.
The random variable <em>X</em> follows a Normal distribution with parameters <em>μ</em> = $225,000 and <em>σ</em> = $50,000.
It is provided that the family has invested in <em>n</em> = 10 different real estate properties.
Then the mean and standard deviation of amount of money that the family has invested in these 10 different real estate properties is:

Now the lowest 80% of the amount invested can be represented as follows:

The value of <em>z</em> is 0.84.
*Use a <em>z</em>-table.
Compute the value of the mean amount invested as follows:


Thus, the amount of money separating the lowest 80% of the amount invested from the highest 20% in a sampling distribution of 10 of the family's real estate holdings is $238,281.57.
Answer:
I believe thw correct answer is B
First compute the component form of vector u by subtracting its initial values from terminal values. 18-1=17, 6-(-12)=18. So u=(17, 18). Since v points in the opposite direction, and has a magnitude three times that of u, we multiply the u by -3 and get v=(-3*17, -3*18)=(-51, -54).