Out of four numbers, whose average is $60,$ the first one is one-fourth of the sum of the last three. The first number is
$15$
$45$
$48$
$60$
The average marks of a class of $35$ children is $35 .$ The marks of one of the students, who got $35,$ was incorrectly entered as $65 .$ What is the correct average of the class?
It rained as much on Wednesday as on all the others days of the week combined. If the average rainfall for the whole week was $3 \,cm $ then how much did it rain on Wednesday? (in $cm$)
The mean weight of $34$ students of a school is $42 \,kg$. If the weight of the teacher be included, the mean rises by $400 \,g$. Find the weight of the teacher (in $kg$).
A person covers $9\, km$ with a speed of $3 \,km / h , 25 \,km$ with a speed of $5\, km / h$ and $30\, km$ with a speed of $10\, km / h$. Find out the average speed of person in $km / h$ ?
The average of marks obtained by $100$ candidates in a certain examination is $30 .$ If the average marks of passed candidates is $35$ and that of the failed candidates is $10,$ what is the number of candidates who passed the examination?