If the mean of $5$ observation $x, x+2, x+4, x+6$ and $x+8$ is $11,$ then the mean of the last three observations is

The average monthly expenditure of a family for the first four months is $Rs.\, 2570$, for the next three months $Rs.\, 2490$ and for the last five months $Rs.\,3030.$ If the family saves $Rs.\, 5320$ during the whole $year,$ the average monthly income of the family during the year is (in $Rs.\,$) 

The average of marks obtained by $150$ candidates in a certain examination is $50 .$ If the average marks of passed candidates is $55$ and that of the failed candidates is $25,$ what is the number of candidates who passed the examination?

The average weight of all the $11$ players of Indian cricket team is $50\, kg.$ If the average of first six lightest weight players is $49\, kg$ and that of the six heaviest players is $52\, kg$. The average weight of the player which lies in the sixth position in the list of players when all the $11$ $players$ are arranged in the order of $increasing$ or $decreasing$ $weights$ (in $kg$)

The average age of a committee of $8$ members is $40 \,years.$ A member, aged $55\, years,$ retired and he was replaced by a member aged $39\, years.$ The average age of the present committee is (in $years$)