Question

If the mean of the observations x + 1 , 2x + 3 , 2x + 7 , 2x + 11 is 30, find the mean of

last two observations and median of all the observations.​

Answer 1

Answer:

Mean of the last 2 observations = 37

Median of all the observations = 33

Step-by-step explanation:

Mean of the given observations = (x+1+2x+3+2x+7+2x+11) / 4 = 30

=> 7x+22 = 120

=> 7x = 98

=> x = 14

So, the mean of the last 2 observations = (4x+18) / 2 = (56+18) / 2 = 74/2 = 37

The given observations when arranged in ascending order,

15, 31, 35, 39

So, median = (31+35) / 2 = 66/2 = 33

Hope this helps you.....

Answer 2

$\huge\boxed{Answer}$

Observations are -

(x + 1) , (2x + 3) , (2x + 7) & (2x + 11) .

Mean of all these observations = 30

(x+1 + 2x+3 + 2x+7 + 2x+11)/4 = 30

7x + 22 = 120

7x = 98

x = 14

So ,

The observations are 15 , 31 , 35 & 39 .

Mean of last two observations :-

= (35 + 39)/2

= 74/2

= 37

Median = (2nd obs. + 3rd obs.)/2

= (31 + 35)/2

= 66/2

= 33