Math, asked by chauhanbabli865, 6 months ago

the avg of a data is 79 . the avg of first two data is 75 if the avy of next four data is 87 . if 8th data is 5 more than 7 th data and one more than 9th data calculate 9th observation?

Answers

Answered by VishnuPriya2801

Answer:-

Given:

Average of a data = 79.

Average of first two data = 75

We know that,

Average = sum of observations/Number of observations.

⟶ 75 = (Sum of first two observations)/2

⟶ 150 = Sum of first two observations

And,

Average of next 4 observations = 87

⟶ Sum of next 4 observations/4 = 87

⟶ Sum of next 4 observations = 87 * 4 = 348

Also given that,

8th observation = 7th observation + 5

8th observation = 9th observation + 1 -- equation (1)

⟶ 7th observation + 5 = 9th observation + 1

⟶ 7th observation = 9th observation + 1 - 5

⟶ 7th observation = 9th observation - 4 -- equation (2)

We can see that the number of observations = 9.

So, Sum of 9 observations/9 = 79

⟶ Sum of 9 observations = 79 * 9

⟶ Sum of 9 observations = 711

⟶ Sum of first two observations + Sum of next 4 observations + 7th observation + 8th observation + 9th observation = 711

Putting the values from equations (1) & (2) we get,

⟶ 150 + 348 + 9th observation - 4 + 9th observation + 1 + 9th observation = 711

⟶ 3 * 9th observation = 711 - 150 - 348 + 4 - 1

⟶ 3 * 9th observation = 216

⟶ 9th observation = 216/3

⟶ 9th observation = 72

Answered by nafibarli789

Answer:

9th observation is 72.

Step-by-step explanation: