The mean weight of six boys in a group is 48 kg. The individual weights of five of them are 51 kg, 45 kg, 49 kg, 46 kg and 44 kg. The weight of the 6th boy is
(a) 52 kg
(b) 52.8 kg
(c) 53 kg
(d) 47 kg
ANSWER:
(c) 53 kg
Weight of the 6th boy = x
Sum of observations = 51 + 45 + 49 + 46 + 44 + x = 235 + x
No: of observations = 6
Mean = sum of observations / no: of observations
48 = 235 + x /6
235 + x = 6 x 48
235 + x = 288
x = 288 - 235
x = 53
The weight of 6th boy = 53 kg