On wikipedia, the definition of Tobin's q is given as:
$$ q=\frac{\text{Market value of installed capital}}{\text{Replacement cost of capital}} $$
Imagine the market value of installed capital is 100\$, and that of replacement capital is \$10. Does $q$ mean that for each dollar of replacement, there are \$10 dollars of market value of that capital? Or simply that the market value of installed capital is 10 times that of replacement capital?
I frequently encounter this interpretation issue. Is there a rule of thumb about when to use which interpretation of division?
From just the formula alone, I don't see how you can come up the word "yields".
It might be an idea of business that it does, or maybe should, yield that much, but that's outside of the mathematical meaning of the formula.
So the math meaning is very much the second one, and you should ask a business professor to what degree the first is intended.
ADDED after comments:
I mean, I can kind of see how you could view them as different concepts. "How many 10 dollars of replacement capital fit into 100 dollars of market valued capital?" is asking
$$ 100 = ? * 10$$
while "market capital per unit of replacement capital", because it uses the magic word "per", asks
$$ ? = 100/10$$
The math fact is that they have the identical solution. Thinking of them as two distinct concepts doesn't strike me as any more useful than distinguishing between "A is 3 inches taller than B" and "B is three inches shorter than A".
I'll also say that thinking of $A/B$ as asking "how many $B$ fit in $A$" is less common. Yes, if you ask "how many dozen is 48 eggs?", then I can see how that corresponds to counting the number of cartons-of-12 you've got. But google tells me that Tobin's Q is some times called the "Q ratio", and ratios almost always say how many A's per B, i.e. your first interpretation, so I'm going to say go with that one.