The weighted arithmetic mean of first 10 natural numbers whose weights are equal to corresponding numbers is equal to

If each of the n numbers xi=i(i=1,2,3,...n)  is replaced by (i+1)xi,then the new mean is

If a variable takes discrete values a+4,a-3.5,a-2.5.a-3,a-2,a+0.5,a+5,a-0.5 where a>0,Then the median of the data is

Four years ago,the average age of A and B was 18 years.Now the average age of A,B and C is 24 years.After 8 years,the age of C will be

The average weight of students in a class is 43kg.Four new students are admitted to the class whose weights are 42kg,36.5kg,39kg and 42.5kg.Now the average weight of the students of the class is 42.5 kg.The number of students in the beginning was

How many right angles triangles can be formed by joining the vertices of a cuboid?