Question

The mean wight of a class of 20 students is 48 kg the two more weighing 60 kg and 58 kg respectively join the class what is the mean of the class now

Answer 1

Mean weight of the class now is 49 kg.

Step-by-step explanation:

We are given that the mean wight of a class of 20 students is 48 kg.

The two more weighing 60 kg and 58 kg respectively join the class and we have to find the mean weight of the class after this.

As we know that, Mean formula is given by;

                 Mean  =  $\frac{\text{Total sum of all the observations}}{\text{Number of observations}}$

                                     Or

                         $\bar X =\frac{\sum X }{\text{n}}$

where,  $\sum X$  =  Total sum of all observations in the data

                 n  =  Number of observations

So,  $\sum X$  =  $\bar X \times n$       {as we are given Mean = 48 kg and n = 20}

Total sum of weight of all 20 students =  $48 \times 20$  =  960 kg

Now, we are are given that two more students join the class weighing 60 kg and 58 kg;

So, the Total sum of weight of all 22 students = 960 + 60 + 58 = 1078 kg.

And the total number of students = 20 + 2 = 22

Therefore, the mean weight of class now  =  $\frac{1078}{22}$ = 49 kg.