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Competitors offered packs of glue sticks, some of which were broken. Correct

Competitors offered packs of glue sticks, some broken. Correct

Competitors offered packs of glue sticks, some of which contained different sizes. Correct

Competitors offered packs of glue sticks, some contained different sizes. Incorrect

Competitors offered packs of glue sticks, some containing different sizes. Correct

If the above in red has accurately labeled the sentences correct or not, is the below a reasonable assumption?

noun + of which + active voice verb can be reduced to noun + active voice ing verb

noun + of which + passive voice verb can be reduced to noun + passive voice verb

Cheers,
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Your sentence assessment is correct and your conclusion seems logical to me...but I wouldn't bet on universal applicability, of course.
Comments  
Thank you. I was hoping this was the answer. Less taxing on the old brain