The average weight of 29 students is 28 kg. By the admission of a new student, the average weight is reduced to 27.1 kg. The weight of the new student is
Choose the correct answer:
A) 22 kg B) 1 kg C) 22.4 kg D) 21 kg E) none of these

Rationale: "exp . the total weight of 29 students = 29 * 28 the total weight of 30 students = 30 * 27.1 weight of the new student = ( 30 * 27.1 – 29 * 28 ) = 813 - 812 = 1 answer : b"
Answer: B