Answer:
The machine can make 9 parts in 2.8 hours.
To find the rate of production, we can divide the number of parts by the time: 9 parts / 2.8 hours = 3.214 parts per hour.
Now that we know the machine's rate of production, we can use it to answer the question:
In 28.0 hours, the machine will produce: 3.214 parts per hour x 28.0 hours = 89.9 parts.
Therefore, the machine can make 89.9 parts in 28.0 hours at the given rate. We can round this to 90 parts.
Explanation: