To represent the calculation "find 7.4 * the difference between 87 and 24", you need to first determine the difference between 87 and 24, and then multiply that result by 7.4.
The difference between 87 and 24 is calculated as \( 87 - 24 \).
Thus, the full expression becomes \( 7.4 * (87 - 24) \).
Therefore, the correct answer is:
D. 7.4 * (87 - 24)