Question

The mean of n numbers
is 15. If same numbers together with 20 have a
mean of 16 then n is
​

Answer 1

Answer:

4

Step-by-step explanation:

Mean = sum of observations / number of observations

Here,

= > 15 = sum of n numbers / n

= > 15n = sum of numbers ... (1)

For new mean,

Sum of observations = 15n + 20

Number = n + 1

Thus,

= > 16 ={15n+20)/(n+1)

= 16( n + 1 ) = 15n + 20

= > 16n + 16 = 15n + 20

= > n = 4