The average weight of $36$ students is $50 \,kg$. It was found later that the figure of $37 \,kg$ was misread as $73 \,kg.$ What is the correct average? (in $kg$)
$49$
$51$
$50.5$
$49.5$
A group of boys has an average weight of $36 \,kg$. One boy weighing $42 \,kg$ leaves the group and another boy weighing $30\, kg$ joints the group. If the average now becomes $35.7\, kg$, then how many boys are there in the group?
Three $years$ ago the average age of a family of $5$ members was $17\, years.$ With the birth of a new baby, the average remains the same three even today. Find out the age of the baby.(in $years$)
The average age of $x$ and $y$ is $20$ $years.$ If $z$ were to replace $x,$ the average would be $19$ and if $z$ were to replace $y$, the average would be $21.$ Find the ages of $x, y$ and $z$.
The mean of $100$ items was $46 .$ Later on, it was discovered that an item $16$ was misread as $61$ and another item $43$ was misread as $34.$ It was also found that the number of items was $90$ and not $100 .$ Then, what is the correct mean?
Out of nine persons$, 8$ persons spent $Rs.\, 30$ each for their meals. The ninth one spent $Rs.\, 20$ more than the average expenditure of all the nine. The total money spent by all of them was (in $Rs.\,$)