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?
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?
- A
$50$
- B
$60$
- C
$75$
- D
$100$
Similar Questions
The average contribution of $5$ men to a fund is $Rs.\,35.$ A sixth man joins and pays $Rs.\,35$ more than the resultant average of $6$ men. The total contribution of all the six men is (in $Rs.$)
The average contribution of $5$ men to a fund is $Rs.\,35.$ A sixth man joins and pays $Rs.\,35$ more than the resultant average of $6$ men. The total contribution of all the six men is (in $Rs.$)
The average of $25$ consecutive odd integers is $55 .$ The highest of these integers is
The average of $25$ consecutive odd integers is $55 .$ The highest of these integers is
The average weight of $8$ sailors in a boat is increased by $1\, kg$ if one of them weighting $56\,kg$ is replaced by a new sailor. The weight of the new sailor is (in $kg$)
The average weight of $8$ sailors in a boat is increased by $1\, kg$ if one of them weighting $56\,kg$ is replaced by a new sailor. The weight of the new sailor is (in $kg$)
$30$ pens and $75$ pencil altogether were purchased for $Rs.\, 510.$ If the average price of $75$ pencil was $Rs.\, 2$ , then what was the average price of a pen? (in $Rs.$)
$30$ pens and $75$ pencil altogether were purchased for $Rs.\, 510.$ If the average price of $75$ pencil was $Rs.\, 2$ , then what was the average price of a pen? (in $Rs.$)
The average marks of a student obtained in Physics, Chemistry and Biology is $70.$ If the student obtained $90\, marks$ in Mathematics, then the new average is
The average marks of a student obtained in Physics, Chemistry and Biology is $70.$ If the student obtained $90\, marks$ in Mathematics, then the new average is