The average age of $5$ members is $21 \,years.$ If the age of the youngest member be $5 \,years,$ find out the average age of the family at the birth of the youngest member.(in $years$)
$24$
$25$
$20$
$28$
Nine friends have a dinner in a hotel. Eight of them spent $Rs.\, 12$ each on their meals and the ninth spent $Rs. \,16$ more than the average expenditure of all the nine. Find out the total money in $Rs.$ spent by them?
The average of three numbers is $28 .$ If first number is half of the second and the $3^{rd}$ number is twice the second, then the third number is?
A person travelled from one place to another at an average speed of $40 \,km / h$ and back to the original place at an average speed of $50\, km / h$. What is his average speed in $km / h$ during the entire trip?
The mean daily profit made by a shopkeeper, in a month of $30\, days,$ was $Rs.\,350.$ If the mean profit for the first $15\, days$ was $Rs.\, 275,$ then the mean profit for the last $15\, days$ would be (in $Rs\,$)
Average age of $15$ students of a class is $15\, years.$ Out of these the average age of $5$ students is $14 \,years$ and that of the other $9$ students is $16\, years.$ The age of the $15^{th}$ student is (in $years$)