Question

Out of 40 boys in a class average weight of 30 is 60 kg and the average weight of remaining is 56 kg then the average weight of whole class is..... ​

Answer 1

Average weight of 30 students = 60kg

Average weight of the remaining students(40-30=10) = 56kg

☞Therefore total weight

= 30*60kg + 10*56kg

= 1800kg + 560kg

= 2360kg

☞Therefore average weight of the class

= 2360kg / 40

= 59kg

Answer 2

Given,

Total number of boys in a class = 40

The average weight of 30 boys = 60 kg

The average of the weights of the remaining 10 boys = 56 kg

To find,

The average weight of the whole class.

Solution,

We can simply solve this mathematical problem using the following process:

Mathematically,

Average = (sum of all the observations)/(total number of observations)

Now, according to the question;

The average of the weights of 30 boys = 60 Kg

=> (sum of the weights of the 30 boys)/30 = 60 Kg

=> sum of the weights of the 30 boys = 60 Kg × 30 = 1800 Kg

And,

The average of the weights of the remaining 10 boys = 56 Kg

=> (sum of the weights of the remaining 10 boys)/10 = 56 Kg

=> sum of the weights of the remaining 10 boys = 56 Kg × 10 = 560 Kg

Now,

The average weight of the whole class

= The average weight of all the 40 boys in the class

= (sum of the weights of all the 40 boys in the class)/40

= {(sum of the weights of the 30 boys) + (sum of the weights of the remaining 10 boys)}/40

= {1800 + 560}/40

= 2360/40 Kg

= 59 Kg

Hence, the average weight of the whole class is 59 Kgs.