# The mean and standard deviation of their combined set of observations will respectively be :

The mean and standard deviation of a set of 16 non-zero positive numbers in an observation are 26 and 3.5 respectively. The mean and standard deviation of another set of 24 non-zero positive numbers without changing the circumstances of both sets of observations, are 29 and 3, respectively. The mean and standard deviation of their combined set of observations will respectively be

(a) 27.8 and 3.21

(b) 36.2 and 3.32

(c) 27.8 and 3.32

(d) 26.2 and 3.21