This problem is from Manhattan Sentence Correction.
Although progress is still difficult to measure, the researchers have found that the benefit of applying interdisciplinary approaches and of fostering cooperation across multiple teams and divisions outweigh any potential cost.
Explanations in the book:
The sentence is incorrect, because "benefit" is singular, so "outweighs" is needed in the sentence.
But I have a little confusion about the problem.
Although progress is still difficult to measure, the researchers have found that the benefit of applying interdisciplinary approaches and (benefit) of fostering cooperation across multiple teams and divisions outweigh any potential cost.
another "benefit" is omitted in front of the second "of", so the sensible structure is that "benefit and benefit outweigh ... ", that is, the "outweigh" should be plural.
are there something wrong here? Many thanks for clarification.