In my native language, and most Indian languages that I know, there is a way to ask for "whichth", but I don't seem to have found anything similar in English. Let me explain below.
What question would you need to ask to obtain the following answers?
- In terms of geographical area, Australia is the sixth largest country.
- John is his father's third son.
- Mars is the fourth planet in the solar system.
The only way I can think of is use of roundabout legalese-like sentence structure, which makes it sound laughable. For example:
- If countries are arranged in order of their geographical area, then at what number is Australia?
- Among the sons of John's father, if you arrange them in the order of birth, then at what number does John appear?
- At what position is Mars in the solar system, in terms of distance from the Sun?
If there is such a word as "whichth", one could ask, for example:
- Australia is "whichth" largest country in terms of geographical area?