Which of these sentences is correct?
Rupees are interchangeable with dollars
or
Rupees is interchangeable with dollars.
Which of these sentences is correct?
Rupees are interchangeable with dollars
or
Rupees is interchangeable with dollars.
To keep it simple... Nouns have 2 groups for number: count and non-count. If you can count them individually, they are count. If you can only measure them, they are non-count (or uncountable). They are handled differently for S-V agreement. Rupees are countable, and take the form of the verb applying to plural. Money, on the other hand, is a concept, uncountable, but still measurable. It takes the singular form of the verb. Thus we would have:
Money is...
but,
Rupees are.
Other example of uncountable nouns: sugar, trouble, gasoline
Examples of count: apple, problem, gas-tank
There some exceptions to be careful of such as school subjects, diseases, names of countries ending in s, etc. and a few others like "news" .
examples: Mathematics, Physics, Statistics, Measles, Mumps,
all of these, including "news" is always singular because the words end in "s". They are not plural.
Rupees are interchangeable with dollars is the correct usage