Answer:
Please find the complete question in the attached file:
Explanation:
For point a:
When X was its random variable of apples, Y the randomized variables of potatoes, then

Your gross profit is represented.
For point b:
The expected value varies as per the random variables:

For point c:
Its variance varies to the square of coefficient (without constants) as well as the standard variance is dependent upon on square root:
For point d:
Yes, because prices are dependent on the apple as well as the prices of potatoes.