(5ab/8c)/(10b/c) = 5ab/8c*c/10b = a/16 if you write them down as fractions you see it more easily :)
The quotient of 8 c 5 ab divided by c 10 b simplifies to 16 a . This is achieved by rewriting the division as multiplication by the reciprocal and then simplifying. The variables c and b cancel in the process, leaving us with the simplified result.
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