The mean weight per student in a group of 7 students is 55 kg. The individual weights of 6 of them (in kg) are 52, 54, 55, 53, 56 and 54. Find the weight of the seventh student.
The mean weight per student in a group of 7 students = 55 kg
Weight of 6 students (in kg) = 52, 54, 55, 53, 56 and 54
Let weight of 7th student = x kg
Therefore, Mean = 
55 = 
385 = 324 + x
x = 385 – 324
x = 61 kg
Therefore, weight of 7th student = 61 kg
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