Three years ago, the average age of a family of $5$ members was $17\, years.$ A baby having been born, the average age of the family is the same today. The present age of the baby is (in $years$)

The sum of three numbers is $98 .$ If the ratio between the first and second is $2: 3$ and that between the second and the third is $5: 8$ , then the second number is

The total marks obtained by a student in Physics, Chemistry and Mathematics together is $120$ more than the marks obtained by him in Chemistry. What is the average marks obtained by him in Physics and Mathematics together ?

The average of prime numbers between $1$ and $20$ is

In an examination average marks obtained by the girls of a class is $85$ and the average marks obtained by the boys of the same class is $87 .$ If the girls and boys are in the ratio $4: 5,$ average marks of the whole class $(approx.)$ is closest to

The average of three consecutive odd numbers is $12$ more than one-third of the first of these numbers. What is the last of the three numbers ?