Answer:
The mean price a randomly chosen customer pays for her or his burger is US$ 3.40
Explanation:
Let's find out the mean of T (total price a randomly chosen customer pays for their burger), this way:
Mean of T = 0.4 * $ 2 + 0.5 * $ 4 + 0.1 * $ 6
Mean of T = 0.8 + 2 + 0.6
Mean of T = US$ 3.40
The mean price a randomly chosen customer pays for her or his burger is US$ 3.40