Question 77

The mean of x , x + 3, x + 5, x + 7, x + 10 is 9. What is the mean ofthe first 3 observations?

Solution

Mean = sum of the observation by no. Of observation

9 = $$\frac{ x + x + 3 +x + 5+ x + 7+x + 10 }{5}$$

9 =

$$\frac{ 5x + 25 }{5}$$

x = 4

so mean of first 3 no. Is

= $$\frac{ 4 + 7 +9 }{3}$$

= 6.66

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