Answer:
Let's let t be the time in minutes that both machines have been working. Then, the number of boxes packed by Machine A in t minutes is 8t, and the number of boxes packed by Machine B in t minutes is 11t.
The difference between the number of boxes packed by Machine B and Machine A is less than 200, so we can write the following inequality:
11t - 8t < 200
Simplifying, we get:
3t < 200
Dividing both sides by 3, we get:
t < 200/3
To the nearest second, this is approximately 66.67 seconds.
Therefore, the possible lengths of time that the machines have been working is t < 66.67 seconds.
Note that this inequality only gives us an upper bound on the time that the machines have been working, since we know that the difference between the number of boxes packed by Machine B and Machine A is less than 200. We do not have any information on the minimum time that the machines have been working, so there are infinitely many possible solutions that satisfy the given conditions.
Explanation: