If the mean of the observation x , 2x+1 , 2x+5 , 2x+ 9 is 30 what is the mean of last to observations ?
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Answered by
10
x+2x+1+2x+5+2x+9=30*4
7x+15=120
x=105/7
x=15
last two observations are 2x+5 and 2x+9
=14+5 and 14+9
mean=(19+23)/2
mean=42/2=21
shahzan:
how did you get 14 the answer must be 30 because 2x is 2×15
Answered by
1
(x + 2x+1 + 2x+5 + 2x+ 9) / 4 = 30
7x = 105
x = 15
Mean of last two observations = 2x+5 + 2x+9)/2
= 59/2
= 29.5
7x = 105
x = 15
Mean of last two observations = 2x+5 + 2x+9)/2
= 59/2
= 29.5
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