15. In a class of 40 students, 15 passed in Mathematics and Science both and 20 passed in only one subject. How many students failed in both the subjects? (A) 5 (B) 25 (C) 20 (D) 45​

The answer may be A.

This is what i found “an explicit formula designates the nth term of the sequence, as an expression of n (where n = the term's location). it defines the sequence as a formula in terms of n. this example is an arithmetic sequence(the same number, 5, is added to each term to get to the next term).” i hope this you for what your looking for. can you plz mark me brainliest?