Answer: To represent the number of correct multiple-choice questions (x) and the number of correct word problems (y) Lorenzo needs to earn a "B," we can use the following inequality:
4x + 8y ≥ 50
This inequality states that the total number of points obtained from multiple-choice questions (4x) and word problems (8y) should be greater than or equal to 50 points to earn a "B" in the class.