Numerical Abili...

The difference between the mean of the first eight composite natural numbers and the mean of the first eight prime numbers, is:

3 numbers whose average is 112, the first number is 1/6th the sum of the other two numbers. What is the first number?

There are 15 students in a class. Their average weight is 40 kg. When one student leaves the class, the average weight is 39.5 kg. What is the weight of the student who left the class (where kg means kilogram)?

A park had an average of 30 children playing on weekdays and an average of 60 children playing on weekends. Find the average number of children playing per day in the park for the month of June beginning with a Saturday.

A truck owner buys petrol at Rs. 6.50, Rs. 7 and Rs. 7.50 per litre for three successive years. What approximately will be the average cost per litre of petrol if he spends Rs. 3200 each year?

Find the average of 1³ + 2³ + 3³ + 4³ .....+ 20³.

The average of the first four numbers is three times the fifth number. If the average of all the five numbers is 85.8, then the fifth number is;

The average age of Ram and Shyam is 28 years. If Rahim replaces Ram, then the average age will become 26 years. If Rahim replaces Shyam, then the average age will become 30 years. What are the respective ages of Ram, Shyam and Rahim?

Including Anni 12 persons, had gone to restaurants in which, every 11 persons spends 64 rupees on food 12^th person spends 66 more rupees than average of all 12 persons then find the total expense on food.

A batsman makes a score of 87 runs in the 17th inning and thus increases his average by 3. Find his average after 17th inning.