Quiz Discussion

If the arithmetic mean of 7, 5, 13, x and 9 is 10, then the value of x is :

• 1] 10
• 2] 12
• 3] 14
• 4] 16

A has 50 coins of 10 paise denominations. While B has 10 coins of 50 paise denominations. C has 20 coins of 25 paise denominations while D has 25 coins of 20 paise denominations. The average number of paise per person is :

• 1] 450 paise
• 2] 500 paise
• 3] 550 paise
• 4] 650 paise

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)

A library has an average of 510 visitors on Sundays and 240 on other days. The average number of visitors per day in a month of 30 days beginning with a Sunday is

• 1]

  285

• 2]

  276

• 3]

  280

• 4]

  290

The average age of 3 children in a family is 20% of the average age of the father and the eldest child. The total age of the mother and the youngest child is 39 years. If the father's age is 26 years, what is the age of the second child ?

• 1] 15 years
• 2] 18 years
• 3] 20 years
• 4] Cannot be determined

A cricketer has a certain average for 9 innings, In the tenth inning he scores 100 runs there by increasing his average by 8 runs. His new average is 

• 1]

  28 runs

• 2]

  24 runs

• 3]

  32 runs

• 4]

  20 runs

If the average of x and 1/x(X\( \ne \)0) is M, then the average of x2 and 1/x² is :

• 1] 1 - M2
• 2] 1 - 2M2
• 3] 2M2 - 1
• 4] 2M2 + 1

The average marks obtained by a class of 60 students is 65. The average marks of half of the students is found to be 85. The average marks of the remaining students is :

• 1] 35
• 2] 45
• 3] 55
• 4] 65

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 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