Question

if mean of the observations x, 2x+1, 2x+5, 2x+9 is 30. What is
mean of last two observation​

Answer 1

32 ANSWER

Step-by-step explanation:

30= x+ 2x+1 + 2x+5 + 2x+9 /4

30×4 = 7x+15

120 = 7x + 15

7x = 120-15

7x = 105

x= 15

so second last observation 2x+5 = 2×15+5 =30+5= 35

last observation 2x+9 = 2×15 +9 = 30+9 = 39

so their mean

$\frac{35 + 39}{2}$

$\frac{64}{2}$

32