The average weight of 29 students is 28 kg. By the admission of a new student, the average weight is reduced to 27.4 kg. The weight of the new student is
Choose one:
A) 22 kg	B) 21.6 kg	C) 22.4 kg	D) 10 kg	E) none of these

Rationale: "exp . the total weight of 29 students = 29 * 28 the total weight of 30 students = 30 * 27.4 weight of the new student = ( 30 * 27.4 – 29 * 28 ) = 822 - 812 = 10 answer : d"
Answer: D