Question

The mean of 15 numbers is 18 and the mean of 10 numbers is 13 . Find the mean of all the 25 numbers

Answer 1

28 is the answer it will help uou

Answer 2

mean of 15 numbers  = (x1+x2----x15)/15

18= (x1+x2-----x15)/15

18*15= (x1+x2----x15)

270 = (x1+x2---x15)

then, the sum of first 15 numbers is 270

mean of last 10 numbers = (x16+x17----x25)/10

13= (x16+x17------x25)/10

13*10 = (x16+17---x25)

130 = (x16+17----25) 

then the sum of last 10 numbers is 130

then then mean of total 25 numbers is 

mean  = (x1+x2----x25)/25

mean  = (270+130)/25

mean = (400)/25

men = 16 



i hope this will help you 



- by ABHAY