Applying the integral formula, it is found that the expected number of coupons a customer will use is of 1.83.
The probability density function is given by:
[tex]f(x) = \frac{4x + 3}{27}, [0,3][/tex]
The integral formula for the expected value is:
[tex]E(x) = \int_0^3 xf(x) dx[/tex]
Hence, applying the formula for f(x) given in this problem, the expected number of coupons a customer will use is:
[tex]E(x) = \int_0^3 \frac{4x^2}{27} + \frac{x}{9} dx[/tex]
[tex]E(x) = \frac{4x^3}{81} + \frac{x^2}{18}|_{x = 0}^{x = 3}[/tex]
[tex]E(x) = 1.83[/tex]
The expected number of coupons a customer will use is of 1.83.
A similar problem, which also involves the calculation of the expected value via integral, is given at https://brainly.com/question/14263236