Question

pls ans to be brainlist

Answer 1

★ Hey mate ★


here is your answer !!

mean = sum of observation / total number of observation



sum of observation => x - 5 + x - 1 + x + x + 2 + x +4 + x + 12


=> 6x + 12 => 6x +12



mean = 6x + 12. / 6



=> 15 × 6 = 6x + 12


90 -12 = 6x



=> 78 = 6x



x = 13


hence , the number is


x - 5

13 - 5 = 8

similarly ,

12 , 13 , 15



hence , the. mean of first four numbers is

sum of observation / total number of observation


8+ 12 + 13 + 15 / 4


=> 48 / 4


=> 12


hence , your answer is ★ 12 ★



hope it helps you dear !!!


thanks !!!
$thanks$

Answer 2

Given that mean of six numbers is 15.

$\frac{x-5+x-1+x+x+2+x+4+x+12}{6} = 15$

x-5 + x - 1 + x + x + 2 + x + 4 + x + 12 = 15 *6 

6x + 12 = 90

6x = 78

x = 13.


Now,


Mean of four numbers = (x - 5 + x - 1 + x + x + 2)/4

                                      = (4x - 4)/4

                                      = 4(13) - 4/4

                                      = 48/4

                                      = 12.


Therefore mean of first 4 numbers = 12.


Hope this helps!