Question

plz solve this problem with explanation

Answer 1

Mean of 10=(sum of 10)/10

7=(sum of 10)/10

7*10=sum of 10 observations

70=sum of 10 observations
________, ___,,,, ________,

Mean of 15=(sum of 15)/15

12=(sum of 15)/15

12*15= sum of 15 observations

180=sum of 15 observations
____, _,,, ______, _, _,

Total mean =(sum of 25)/25

Mean =(70+180)/25

Mean = (250)/10

Mean=10

Mean of all observations =10


I hope this will help you



-by ABHAY