Problems on Averages

Average age of $5$boys is $16 years$, of which that of$4$ boys is $16 years 3 months$. The age of the $5th$ boy is

A train goes from Ballygunge to Sealdah at an average speed of $20 km./hr$. and comes back at an average speed of $30 km./hr.$ The average speed of the train for the whole journey is -

The average price of $3$ diamonds of same weights is $₹5 crore$, where the average price of the two costliest diamonds is double the price of the cheapest diamond. The price of the cheapest diamond is ?

The average age of the Indian football team is $30 \mathrm{years}$. The average age of $5$ of the players is $29 \mathrm{years}$ and that of another set of $5$ players, totally different from the first five, is $27 \mathrm{years}$. If it is the captain who was not included in either of these two group, then find the age of the captain _____.

The average of $20$ numbers is zero. Of them, at the most, how many may be greater than zero $?$

The average of four consecutive even numbers is$27$. find the largest of these numbers.

The average age of $27$ girls and the teacher is $14$ $years$. When the teacher's age is excluded, the average age decreases by $1$. What is the age (in year) of teachers?

From a class of $42$ boys, a boy aged $10$ years goes away and in his place a new boy is admitted. If on account of this change, the average age of the boys in that class increased by $2$ months, the age of the newcomer is :

The average of ten numbers is $50$, that of the first four is $40$ and the next three is $25$. The eight number is less than the ninth by $7$, and less than the tenth by $12.$ Then, tenth number is—

A travel agency has three types of vehicles viz. four seater, auto rickshaw, 10 seater maxi cab and 20 seater minibus. The rate of each passenger (irrespective of its age or weight or seniority) for the auto rickshaw is Rs. 12 and for the maxi cab is Rs. 15 and for the minibus is Rs. 8 for the one round. The average occupancy of the seats is 100%, 80% and 75% respectively. If he has one vehicle of each kind, then the average earning for one round of each vehicle is :

The average of $10$ numbers is $40.2$. Later it is found that two numbers have been wrongly added. The first is $18$ greater than the actual number and second number added is $13$ by mistake instead of $31$. Find the correct average.

The average temperature of the first three days is $22°\mathrm{C}$ and of the next three days is $24°\mathrm{C}$. If the average temperature of the whole week is $23.5°\mathrm{C}$, what is the temperature of the last day of that week?

The average of $8$ numbers is$132$. If one number is excluded, the average of the remaining $7$numbers is $130$. The excluded number is-

In a class with a certain number of students, if one new student weighing $50 \mathrm{kg}$ is added, then the average weight of the class increased by $1 \mathrm{kg}$. If one more student weighing$50 \mathrm{kg}$ is added, then the average weight of the class increases by$1.5 \mathrm{kg}$ over the original average. What is the original weight ($\mathrm{in} \mathrm{kg}$) of the class?

A man on tour travels first $160$ km at $64$ km/hr and the next $160$km at $80$km/hr. The average speed for the first $320$km of the tour is$:$

The average of 1000.0001, 100.001, 10.01, 1.1 is :

The average salary of the entire staff in an office is $₹200$ per day. The average salary of officers is $₹550$ and that of non officers is $₹120$. If the number of officers is 16, then find the numbers of non-officer in the office.

In a class of 30 students, the average weight of boys is 20 kg and the average weight of the girls is 25 kg. The fraction of boys out of the total students of the class is :

The average marks of 28 students in mathematics was 50. 8 students left the school and then this average increased by 5. What is the average marks obtained by the students who left the school?

$5$ members of a team are weighed consecutively and their average weight calculated after each member is weighted. If the average weight increases by one $kg$ each time, how much heavier is the last player than the first one?