A can copy 50 papers in 10 hrs, while A & B can copy 70 papers in 10 hrs. How many hours are required for B to copy 26 papers?  Answers:
A) 11 hours	B) 12 hours	C) 13 hours	D) 14 hours	E) 18 hours

Rationale: a can copy 50 papers in 10 hrs , while a & b can copy 70 papers in 10 hrs . it means b can copy 20 papers in 10 hrs . then time taken by b to copy 26 papers = 26 * 10 / 20 = 13 hours answer : c
Answer: C