Question

The mean of 10 numbers is 7 and the mean of 15 other numbers is 12 find the mean of these 25 numbers taken together

Answer 1

Let the sum of first 10 numbers be a

And sum of other 15 numbers be b

Mean of first 10 numbers = 7

=> a/ 10 = 7

=> a = 70


Mean of other 15 numbers = 12

=> b / 15 = 12

=> b = 180


Sum of 25 numbers = a+b
= 70 + 180
= 250

Mean of 25 numbers = 250 / 25 = 10

Answer 2

Answer:

Let the sum of first 10 numbers be a

And sum of other 15 numbers be b

Mean of first 10 numbers =7

=>a/10=7

=>a=70

Mean of other 15 numbers rs = 12

=>b/15=12

=>b=180

Sum of 25 numbers s = a + b =70+180

=250

Mean of 25 bers = 250/25 = 10

EDITING,

HAAA THE 2 ANS IS SAME

I THINK AS WE USE SAME SITE?