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 cricketer whose bowling average is 12.4 runs per wicket takes 5 wickets for 26 runs and thereby decreased his average by 0.4. The number of wickets taken by him the last match was-

• 1] 64
• 2] 72
• 3] 80
• 4] 85

The present age of a father is 3 years more than three times the age of his son. Three years hence, father's age will be 10 years more than twice the age of the son. The father's age is :

• 1] 33 years
• 2] 39 years
• 3] 45 years
• 4] 40 years

The average of 11 players of a cricket team is decreased by 2 months when two of them aged 17 years and 20 years are replaced by two new players. The average age of the new players is-

• 1] 17 years 1 month
• 2] 17 years 7 months
• 3] 17 years 11 months
• 4] 18 years 3 months

One-fourth of certain journey is covered at the rate of 25 km/h, one-third at the rate of 30 km/h and the rest at 50 km/h. Find the average speed for the whole journey.

• 1]

  600/53 km/h

• 2]

  1200/53 km/h

• 3]

  1800/53 km/h

• 4]

  1600/53 km/h

• 5]

  None of these

The average of five numbers is 7. If three new numbers would be added, then the new average comes out to be 8.5. What is the average of those three new numbers ?

• 1] 9
• 2] 10.5
• 3] 11
• 4] 11.5

In a boat there are 8 men whose average weight is increased by 1 kg when 1 man of 60 kg is replaced by a new man. What is weight of new comer?

• 1] 70 kg
• 2] 66 kg
• 3] 68 kg
• 4] 69 kg

If the mean of a,b,c is M and ab+bc+ca=0, then the mean of a²,b²,c² is:

• 1]

  M²

• 2]

  3M²

• 3]

  6M²

• 4]

  9M²

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

The average annual income (in Rs.) of certain agricultural workers is S and that of other workers is T. The number of agricultural workers is 11 times that of other workers. Then the average monthly income (in Rs.) of all the workers is 

• 1]

  (S+T)/2

• 2]

  (S+11T)/2

• 3]

  (1/11S)+T

• 4]

  (11S+T)/12