The average weight of a class of 24 students is 35 kg. If the weight of the teacher be included, the average rises by 400 g. The weight of the teacher is	Answers.
A) 45 kg B) 50 kg C) 53 kg D) 55 kg E) none of these

Rationale: "solution weight of the teacher = ( 35.4 × 25 - 35 × 24 ) kg = 45 kg . answer a"
Answer: A