The average of marks in Mathematics for 5 students was found to do 50. Later, it was discovered that in the case of one …

The average of 8 numbers is 20. The average of first two numbers is $$15\frac{1}{2}$$ and that of the next three is $$21…

A man had 7 children. When their average age was 12 years, a child aged 6 years died. Then average age of remaining six …

The total marks obtained by a student in Physics, Chemistry and Mathematics together is 120 more than the marks obtained…

The mean of 9 observation is 16. One more observation is included and the new mean becomes 17. The 10<sup>th</s…

Out of 20 boys, 6 are each of 1 m 15 cm height, 8 are of 1 m 10 cm and rest of 1 m 12 cm. The average height of all of t…

The average age of 3 children in a family is 20% of the average age of the father and the eldest child. The total age of…

When the average age of a couple and their son was 42 years, the son married and got a child after one year. When the ch…