In an exam, the average marks obtained by the students was found to be 60. After omission of computational errors, the average marks of 100 candidates had to be changed from 60 to 30 and the average with respect to all the examinees came down to 45 marks. The total number of candidates who took the exam, was. 

The average of seven numbers is 18. If one of the number is 17 and if it is replaced by 31, then the average becomes: 

The average of four consecutive even numbers is 15. The 2nd highest number is: 

Eight consecutive numbers are given. If the average of the two numbers that appear in the middle is 6, then the sum of the eight given numbers is: 

If P= 2² + 6² + 10² +14² +……..94² and Q=1² + 5² + 9² +……..81², then what is the value of P- Q ?

Which of the following statements is /are True?
I. $$ {33^3}>{3^{33}}$$
II. $$ {333}>{(3^{3})^{3}}$$

The angle of elevation of the top of a tree 220 metres high from two points lies on the same plane are 30° and 45°. What is the distance (in metres) between the two points?

The distance between the tops of two building 38 metres and 58 metres and high is 52 metres. What will be the distance (in metres) between two building?