Final answer:
The correct expression for '10 subtracted from the quotient of 3 and a number' is '3/n - 10', which reflects division followed by subtraction.
Step-by-step explanation:
The expression that represents "10 subtracted from the quotient of 3 and a number" is '3/n - 10'. When the word 'quotient' is mentioned, we are referring to the result of division. Thus, if 'n' denotes the unspecified number, then '3 divided by n' is expressed as '3/n'. From this quotient, we need to subtract 10, which gives us the expression '3/n - 10'.