Out of $9$ persons$, 8$ persons spent $Rs.\, 30$ each for their meals. The nineth one spent $Rs.\, 20$ more then the average expenditure of all the nine. The total money spent by all of them was (in $Rs.$)

A man spends $Rs.\,1800$ monthly on an average for the first four months and $Rs.\,2000$ monthly for the next eight months and saves $Rs.\,5600$ a $year$. His average monthly income is (in $Rs.$)

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 ?

$30$ pens and $75$ pencil altogether were purchased for $Rs.\, 510.$ If the average price of $75$ pencil was $Rs.\, 2$ , then what was the average price of a pen? (in $Rs.$)

The average age of $30$ women decreases by $3$ $months$ if a new person Neha is included in place of a $25\, year$ old woman. Calculate the age of Neha in $year$ ?

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 twas $90$ and not $100 .$ Then what is the correct mean?