Question

if the Mean of the observation x x +3 x +5 x +7 and x + 10 is 9 then find the mean of the last three observation

Answer 1

Mean=x+x+3+x+5+x+7+x+10/5
9×5=5x+25
45-25=5x
5x=20
x=20/5
x=4
Observations are x=4
x+3=4+3=7
x+5=4+5=9
x+7=4+7=11
x+10=4+10=14
Mean of last three observation
mean=9+11+14/3
=34/3
=11.3

Answer 2

YOUR ANS IS IN THIS PHOTO.

NOW MEAN = 9+11+14/3

==>>> 34/3


==>> 11.3 (ANS)