A student has scores of 58.5, 56.75, and 62.25 on his first three tests. He needs an average of at least 60 to earn a grade of D. What is the minimum score that the student needs on the fourth test to ensure a D?

1. Sum the scores of the first three tests:
58.5 + 56.75 + 62.25 = 177.5
2. Set up the inequality for the average of the four tests:
\frac{177.5 + x}{4} \geq 60
3. Multiply both sides by 4 to clear the denominator:
177.5 + x \geq 240
4. Subtract 177.5 from both sides to solve for \( x \):
x \geq 62.5
Answer: The minimum score that the student needs on the fourth test to ensure a D is 62.5.