There are three groups A,B,C with 22,18 and 10 students respectively. The mean weight of the combined set of 50 students is found to be 47.6kg. If the mean weights of groups A and B are 40kg and 50kg respectively, calculate the mean weight of group C.

sum of all the weight / 50 = 47.6

sum of all weights = 2380 kg

mean of group A = sum of 22 weights / 22 = 40

sum of 22 weights = 22 x 40 = 880 kg

Now,

Mean of group B = sum of 18 weights / 18 = 50kg

So, sum of 18 weights = 50 x 18 = 900 kg

Now,

sum of of Group C = total weight - (weight A + weight B )

= 2380 - ( 880 + 900 )

= 2380 - 1780 = 600kg

So mean weight of group C = 600 / 10 = 60kg

I think it should be the answer