An aeroplane flies along the four sides of a square field at speeds of $200,400,600$ and $800\, km / hr$. The average speed of the plane in the flight around the field in $km / hr$ is:
$384$
$400$
$500$
$284$
The average of a non-zero number and its square is $5$ times the number. The number is
A batsman in his $17^{th}$ innings, makes a score of $85$ runs, and there by, increases his average by $3$ runs. What is his average after the $17^{th}$ innings ? He had never been $'not out'.$
The average annual income (in $Rs.$) of certain agricultural workers is $S$ and that of other workers is $T$. The number of agricultural workers is $11$ times that of other workers. Then the average annual income (in $Rs.$) of all the workers 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 average weight of $3$ person is $65 \,kg$. If a fourth person having a weight of $45 \,kg$ joins the group, what is the average weight of the group ? (in $kg$)