Question 15

Explanation

Work Rate Analysis

Work rate is the portion of work completed per unit of time (1 minute). Based on the problem:

Combined Work Calculation

If the three machines work together for $6$ minutes, the total work completed is the sum of their rates multiplied by time:

Simplify the fraction $\frac{4}{32}$ to $\frac{1}{8}$:

In decimal form, $\frac{3}{4}$ is equal to $0.75$.

Thus, the completed work is $0.75$ part.