<h3>
Answer: 20 hours</h3>
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Explanation:
We have two workers, more or less. Worker A gets the job done in 5 hours. Worker B comes along to help. If A and B work together, they get the job done in 4 hours. This assumes neither worker hinders the other.
Worker A's rate is 1/5 of a job per hour. In other words, after 1 hour, 1/5 of the job is done.
The combined rate is 1/4 for similar reasoning
Worker B's rate is 1/x where x represents how long it takes worker B to get the job done on its own.
The equation to solve is
1/5 + 1/x = 1/4
Note how 1/5 and 1/x represents the sum of the individual rates to get the combined rate 1/4
To solve this equation, it helps to clear out the fractions. Multiply every term by the LCD 20x
20x(1/5 + 1/x) = 20x(1/4)
20x(1/5) + 20x(1/x) = 20x(1/4)
4x + 20 = 5x
From here you can probably see solving this is relatively easy
4x+20 = 5x
20 = 5x-4x
20 = x
x = 20
Therefore, it will take 20 hours for worker B to get the job done on its own.
Going back to the processing context, it takes 20 hours for the new processor to download the movie. This is where the new processor is working alone without help from the original processor.
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Side note: downloading a movie really depends on internet speed rather than processor speed.
