Question

An additional value 15 is included in a series of 11 values and the mean remains unchanged. The mean of the series was:
(A) 12
(B) 15
(C) 20
(D) None of these
please give right answer.
who give right answer I will mark him or her as brainliest.. ​

Answer 1

★ Given  :-

• An additional value 15 is included in a series of 11 values and the mean remains unchanged.

Step-by-step explanation:

★ To Find  :-

• Find the mean of the series.

★ Solution :-

• Let it be 'x'

• The sum of observations = 11 x  

• 15 is included with 11 x

• The sum of all observations = ${\bold{\boxed{\bold{\ 11 x + 15}}}}$

• Total number of observations ${\boxed{\bold{\ 11 + 1{\bold{\ = 12}}}}}$

• ${\boxed{\bold{\ x ={\bold{\ 12 x = 11x{\bold{\ + {\ 15}}}}}}}$

•  ${\boxed{\bold{\longtrow{\ x = 15}}}$

• ${\bold{\red{\boxed{\green{\blue{Correct~option~ is~ (B)}}}}}}}}$

${\boxed{\bold{\pink{Hence~ stated}}}$

Answer 2

↔↔↔↔↔

15 is your correct answer

x = x15

Step-by-step explanation: