Questions: The time needed for cutting and molding a workpiece is 8 minutes and 13 minutes respectively. A welder must produce 5 such pieces. If he begins working at 1 PM , what time will he complete the work?

Solution Steps

The time needed to cut one workpiece is 8 minutes, and the time needed to mold one workpiece is 13 minutes. Therefore, the total time required to complete one workpiece is:

\[ 8 \text{ minutes} + 13 \text{ minutes} = 21 \text{ minutes} \]

Since the welder needs to produce 5 workpieces, we multiply the time for one workpiece by 5:

\[ 21 \text{ minutes/workpiece} \times 5 \text{ workpieces} = 105 \text{ minutes} \]

The welder starts working at 1 PM. We need to add 105 minutes to this start time to find the completion time.

First, convert 105 minutes into hours and minutes:

\[ 105 \text{ minutes} = 1 \text{ hour} + 45 \text{ minutes} \]

Add this to the start time:

• Start time: 1:00 PM
• Add 1 hour: 2:00 PM
• Add 45 minutes: 2:45 PM

Final Answer