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 $km / h$ ?
$5 \frac{9}{11}$
$11 \frac{5}{9}$
$9 \frac{5}{11}$
$5 \frac{5}{11}$
Last year, $5$ companies had an average of $16$ non working days each, and $2$ companies had $5$ fewer non working days each. What was the average number of non working days given by the same companies this $year$ ?
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 obtained by $150$ students in an examination is $40 .$ If the average marks of passed students is $60$ and that of the failed students is $20,$ what is the number of students who passed the examination ?
The average of three numbers is $154 .$ The first number is twice the second and the second number is twice the third. The first number is
The average marks of students in an examination was $65 .$ It was later found that the marks of one students had been wrongly entered as $83$ instead of $38.$ the correct average is ?