Aptitude ➤ Averages ➤ Set 2

#### Averages : Important Facts and Formulae

Average:
Average = Sum of observations / Number of observations

Average Speed :
Suppose a man covers a certain distance at x kmph and an equal distance at y kmph.
Then, the average speed druing the whole journey is [2xy/(x+y)] kmph.
Question 1
Q1.  David obtained 76, 65, 82, 67 and 85 marks (out of 100) in English, Mathematics, Physics, Chemistry, and Biology. What are his average marks?
Question 2
Q2.  In Arun's opinion, his weight is greater than 65 kg but less than 72 kg. His brother does not agree with Arun and he thinks that Arun's weight is greater than 60 kg but less than 70 kg. His mother's view is that his weight cannot be greater than 68 kg. If all of them are correct in their estimation, what is the average of different probable weights of Arun?
Question 3
Q3.  The average of 20 numbers is zero. Of them, at the most, how many may be greater than zero?
Question 4
Q4.  Find the average of all the numbers between 6 and 34 which are divisible by 5.
Question 5
Q5.  A student was asked to find the arithmetic mean of the numbers 3, 11, 7, 9, 15, 13, 8, 19, 17, 21, 14 and x. He found the mean to be 12. What should be the number in place of x ?