5/6
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To find the ratio of the number of semi-skilled workers to the number of skilled workers, we need to divide the number of semi-skilled workers by the number of skilled workers.
In this case, there are 25 semi-skilled workers and 30 skilled workers, so the ratio is:
To simplify this ratio, we can divide both the numerator and the denominator by their greatest common divisor, which is 5.
So the simplified ratio is 5/6.