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)

Ajit has a certain average for 9 innings. In the tenth innings, he scores 100 runs thereby increasing his average by 8 runs. His new average is:

• 1] 20
• 2] 21
• 3] 28
• 4] 32

A batsman makes a score of 87 runs in the 17^th inning and thus increases his average by 3. Find his average after 17^th inning.

• 1]

  40

• 2]

  39

• 3]

  52

• 4]

  55

The average of 6 numbers is 7. The average of three numbers of them is 5. What will be the average of remaining numbers?

• 1] 15
• 2] 30
• 3] 9
• 4] 42

30 pens and 75 pencils altogether were purchased for Rs. 510. If the average price of a pencil was Rs. 2, what was the average price of a pen ?

• 1] Rs. 9
• 2] Rs. 10
• 3] Rs. 11
• 4] Rs. 12

a, b, c, d, e, f, g are consecutive even numbers. j, k, l, m, n are consecutive odd numbers. The average of all the numbers is :

• 1]

  \(3\left( {\frac{{a + n}}{2}} \right)\)

• 2]

  \(\left( {\frac{{1 + d}}{2}} \right)\)

• 3]

  \(\left( {\frac{{a + b + m + n}}{4}} \right)\)

• 4]

  \(3\left( {\frac{{j + c + n +g}}{4}} \right)\)

The average of the ages of Sumit, Krishna and Rishabh is 43 and the average of the ages of Sumit, Rishabh and Rohit is 49. If Rohit is 54 years old, what is Krishna’s age?

• 1] 24 years
• 2] 36 years
• 3] 45 years
• 4] Cannot be determined
• 5] None of these

There were 35 students in a hostel. Due to the admission of 7 new student, the expenses of the mess were increased by Rs. 42 per day, while the average expenditure per head diminished by Re 1. What was the original expenditure of the mess?

• 1]

  432

• 2]

  442

• 3]

  420

• 4]

  415

The arithmetic mean of the scores of a group of students in a test was 52. The brightest 20% of them secured a mean score of 80 and the dullest 25% a mean score of 31. The mean score of remaining 55% is-

• 1] 45
• 2] 50
• 3] 51.4 approx
• 4] 54.6 approx

The average expenditure of a man for the first five months is Rs. 1200 and for the next seven months is Rs. 1300. If he saves Rs. 2900 in that year, his monthly average income is-

• 1] Rs. 1500
• 2] Rs. 1600
• 3] Rs. 1700
• 4] Rs. 1400