3. (6 points) Two apprentices, A and B, are discussing who will work with the master to process a batch of parts. A says: "If I work with the master, then I will complete 20% of the entire work." B says: "That's nothing, if I work with the master, then I will complete 40% of the entire work." At this moment, the master comes and says to B: "If A joins us to help, you can process 60 fewer parts." If what they said is all correct, then the total number of parts in this batch is $\qquad$.
【Answer】Solution: Jia says, "If I work with my master, then I will complete 20% of the entire work." This indicates the ratio of Jia's speed to the master's speed is $20\% \div (1-20\%) = 1: 4$,

Yi says, "That's nothing, if I work with the master, then I will complete 40% of the entire work." This indicates the ratio of Yi's speed to the master's speed is $40\% \div (1-40\%) = 1: 1.5$,

The master comes and says to Yi, "If Jia joins us to help, you can process 60 fewer parts." This indicates the proportion of the task completed by Yi is $\frac{\frac{1}{1.5}}{\frac{1}{4}+\frac{1}{1.5}+1}$, the total number of parts in this batch is $60 \div \left[40\% - \frac{\frac{1}{1.5}}{\frac{1}{4}+\frac{1}{1.5}+1}\right] = 60 \div \frac{6}{115} = 1150$.

Therefore, the answer is 1150.