Ashish has earned an average of $4200$ dollars for the first eleven months of the year. If he justifies his staying on in the US on the basis of his ability to earn at least $5000$ dollars per $month$ for the entire $year,$ how much should heearn (in $dollars$) in the last $month$ to achieve his required average for the whole $year$ ?

Of three numbers, the second is thrice the first and the third number is three-fourths of the first.If the average of the three numbers is $114,$ the largest number is

Roshan bought $5$ pants at $Rs.\, 25$ each, $10$ shirts at $Rs.\, 50$ each and $15$ ties at $Rs.\, 35$ each. Find the average price of all the articles in $Rs.$ 

The average age of $8$ members of a group is $40 \,years.$ The age of $1$ member is $55\, years.$ After his retirement a new member comes in his place of age $39 .$ What is the effect of his retirement on the average age of group ?

The average of $13$ results is $60 .$ If the average of first $7$ results is $59$ and that of last $7$ results is $61,$ what will be the seventh result $?$

The average of $17$ numbers is $10.9 $ If the average of first nine numbers is $10.5$ and that of the last $9$ numbers is $11.4,$ the middle number is