Question

17) The mean of 12 observation is 10. If one
number is included the mean of number
becomes 11 then find the new number
included.​

Answer 1

Answer:

The number is 9

Step-by-step explanation:

Because 1st method 12 is 10 so, the 9 will 11.

2nd method is if 10 +2: 12 so,9 +2: 11.

Answer 2

Step-by-step explanation:

given,

n1=12

x1=10

since mean=sum of observations÷no.of observations

=>sum of observations=10×12=120

let new number be 'a'=>(120+a)/11=11

=>120+a=121

so a=121-120=1

there the new number is 1