The average of $6$ observations is $12 .$ A new seventh observation is included and the new average is decreased by $1$. The seventh observation is
$1$
$3$
$5$
$6$
Seventh observation
$=7 \times 11-6 \times 12=5$
The average of $7$ consecutive numbers is $20 .$ The largest of these numbers is
If the difference between the average of $x, y$ and $y$, $z$ is $12,$ then the difference between $x$ and $z$ is
Average rainfall on Monday, Tuesday, Wednesday and Thursday is $420.5\, cm$ and average on Tuesday, Wednesday, Thursday and Friday is $440.5\, cm .$ If the ratio of rainfall for Monday and Friday is $20: 21,$ find the rainfall in $cm$ on Monday and Friday.
The average age of $20$ boys in the class is $15.6\, years.$ Five new boys join and the new average becomes $15.56\, years.$ What is the average age of the five new boys? (in $years$)
Visitors to a show were charged $Rs.\,15.00$ each on the first day, $Rs.\, 7.50$ on the second and $Rs.\, 2.50$ on the third day. Visitors total attendance for three days were in the ratio $2: 5: 13$ . Find out the average charge per visitor for the entre show. (in $Rs.$)
