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?
$125$
$120$
$140$
$160$
The average monthly salary of a staff of $9$ persons is $Rs.\,2450.$ One member of the staff whose monthly salary is $Rs.\,2650$ is transferred. Find out the average salary of the remaining $8$ persons of the staff.(in $Rs.$)
The average age of $11$ players of a cricket team is increased by $2 \,months$ when two of them aged $18\, years$ and $20 \,years$ are replaced by two new players. The average age of the new players is?
The average of runs of a cricket player of $10$ innings was $32 .$ How many runs must he make in his next innings so as to increase his average of runs by $4 \,?$
The mean weight of $150$ students in a class is $60 \,kg.$ The mean weight of boys is $70\, kg$ and that of girls is $55 \,kg$. What is the number of boys in the class?
Eleven years earlier the average age of a family of $4$ members was $28 \,years.$ Now the age of the same family with six members js yet the same, even when $2$ children were born in this period. If they belong to the same parents and the age of the first child at the time of the birth of the younger child was same as there were total family members just after the birth of the youngest member of this family, then the present age of the youngest member of the family is in $year$?