The average age of a family of 5 members is 20 years. If the age of the youngest member be 10 years then what was the av…

The arithmetic mean of first 11 natural numbers is

The average weight of 8 person's increases by 2.5 kg when a new person comes in place of one of them weighing 65 kg. Wha…

Distance between two stations A and B is 778km. A train covers the journey from A to B at 84 km per hour and returns bac…

If the average of 5 numbers is 10, the number which should be added to make the average 12 is-

The average of 6 observations is 45.5. If one new observation is added to the previous observations, then the new averag…

There are 3 groups of students, each containing 25, 50 and 25 students respectively. The mean marks obtained by the firs…

There are 30 students in a class. The average age of first 10 students is 12.5 years. The average age of the remaining 2…