Quiz Discussion

The average of x number is y and average of y numbers is x. Then the average of all the numbers taken together is

• 1]

  (x+y)/2xy

• 2]

  2xy/(x+y)

• 3]

  (x²+y²)/(x+y)

• 4]

  xy/(x+y)

Total expenses of a boarding house are partly fixed and partly varying linearly with the number of boarders. The average expense per boarder is Rs. 700 when there are 25 boarders and Rs. 600 when there are 50 boarders. What is the average expense per boarder when there are 100 boarders?

• 1] Rs. 540
• 2] Rs. 550
• 3] Rs. 570
• 4] Rs. 580

If 25a + 25b = 115, what is the average of a and b?

• 1] 2.5
• 2] 3.4
• 3] 4.5
• 4] 4.6
• 5] None of these

The average of first five multiples of 3 is:

• 1] 9
• 2] 10
• 3] 8
• 4] 11

The average of 20 numbers is zero. Of them, at the most, how many may be greater than zero ?

• 1]

  0

• 2]

  -1

• 3]

  1

• 4]

  None Of These

Average of two numbers is 8 and average of other three numbers is 3; the average of the five numbers is :

• 1] 2
• 2] 3
• 3] 5
• 4] 6

Average weight of 25 students of a class is 50 kg. If the weight of the class teacher is included , the average is increased by 1 kg. The weight of the teacher is ?

• 1] 76 kg
• 2] 77 kg
• 3] 74 kg
• 4] 75 kg

A cricketer had a certain average of runs for his 64 innings. In his 65th innings, he is bowled out for no score on his part. This brings down his average by 2 runs. His new average of runs is :

• 1] 130
• 2] 128
• 3] 70
• 4] 68

David obtained 76, 65, 82, 67 and 85 marks (out of 100) in English, mathematics, physics, chemistry and biology. What are his average marks?

• 1] 65
• 2] 69
• 3] 75
• 4] None of these

A set A consists of integers 27, 28, 30 and 33. If integer k is included in the set, the average of set A will increase by 30%. What is the value of integer k ?

• 1] 68
• 2] 79
• 3] 73.75
• 4] 75.25