The average weight of some students in a class was 58.4 kg. When 5 students having the average weight 62.8 kg joined the class, the average weight of all students in the class increased by 0.55 kg. The number of students initially in the class, were:

35

Let total number of students be x after joining 5 students, then

0.55x = 5 (62.8 - 58.4)

x = 40

Number of students in the class were = 40 - 5 = 35