Question

the mean of 7 observations is 20. if the mean of the first 4 onservation is 12 and that of last 4 observations is 28 find the 4th observation.

Answer 1

the 4th term is 20 ...
this question can be solved by applying logic
I hope u understood

Answer 2

Dear Student,

● Answer -

4th observation = 20

● Explanation -

Sum of 7 observations of is 7 × 20 = 140.

Sum of first 4 observations is 4 × 12 = 48.

Sum of last 4 observations is 4 × 28 = 112.

4th observation is calculated as -

4th observation = (sum of first 4 observations + sum of last 4 observations) - sum of 7 observations

4th observation = (48 + 112) - 140

4th observation = 160 - 140

4th observation = 20

Hence, 4th observation is 20.

Thanks dear. Hope this helps you...