If an engine develops 108 horsepower at 87 percent power, what horsepower would it develop at 65 percent power?

To determine the horsepower an engine would produce at a lower percentage of power based on its performance at a higher percentage, a proportional relationship can be used.

First, understand that the horsepower output is directly related to the percentage of power being utilized. If the engine produces 108 horsepower at 87 percent power, we can use the ratio of these two percentages to estimate the horsepower at 65 percent power.

Set up a proportion based on the horsepower and the respective power percentages:

If 108 horsepower is produced at 87 percent power, then at 65 percent power, the horsepower can be calculated by proportion:

108 horsepower / 87 percent = X horsepower / 65 percent.

Cross-multiply to find X:

X = (108 horsepower * 65 percent) / 87 percent.

Calculating this gives:

X = (108 * 65) / 87, which simplifies to approximately 81 horsepower.

Thus, at 65 percent power, the engine would develop around 81 horsepower, which corresponds to the correct answer. This demonstrates the concept that as power percentage decreases, the horsepower output decreases proportionally, allowing for straightforward calculations when adjusting for different power levels.