Madhav ranks seventeenth in a class of thirtyone. What is his rank from the last?	Choose the correct answer:
A) 13	B) 14	C) 15	D) 16	E) 17

Rationale: ( rank from top ) + ( rank from bottom ) - 1 = total students 17 + x - 1 = 31 x = 15 answer : c
Answer: C