Question

The mean wieight of five students is 51 kg and the mean weight of four students is 54 kg.The mean weight of nine studemts will be ---

Answer 1

mean weight of one students = 51/5=10.2

mean weight of one student(second condition) =54/4=13.5

mean weight of all students= (51+54)/9=57 kg
mean weight of one student=57/9=6.333333333kg

mean weight of nine student= 6.333333333*9