Final answer:
The expected value of the weekly gravel sales is 3/2.
Step-by-step explanation:
To find the expected value of a random variable, we need to multiply each possible value x by its corresponding probability f(x) and sum them up. In this case, the possible values of x are between 0 and 10. For 0 < x < 10, the probability density function (pdf) is given by f(x) = \frac{3}{2}(1 - x^2). For all other values of x, the probability is 0.
We can calculate the expected value as follows:
- Multiply each value of x between 0 and 10 with its corresponding probability f(x)
- Sum up all the products
Doing the calculations, we find that the expected value is 3/2 or option A.