The average of $50$ numbers is $38$. If two numbers $45$ and $55$ are discarded,the average of the remaining set of numbers is:

The average of $6$ numbers is $20$. If one number is removed, the average becomes $15$. What is the number removed?

The average age of Seema,Sapna,Asha,Kavita,and Atrye is $40 \text{ years}$. The average age of Seema and Sapna is $35 \text{ years}$,and the average age of Asha and Kavita is $42 \text{ years}$. What is the age of Atrye?

The average earning of a mechanic for the first four days of a week is $Rs. 18$ and for the last four days is $Rs. 22$. If he earns $Rs. 20$ on the fourth day,his average earning for the whole week is (in $Rs.$)

In an entrance examination,Ritu scored $56$ percent marks,Smita scored $92$ percent marks,and Rina scored $634$ marks. The maximum marks of the examination is $875$. What is the average marks scored by all the three girls together?

Out of four numbers,the average of the first three is $16$ and that of the last three is $15$. If the last number is $20$,then the first number is: