Quiz Discussion

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 age of the boys in a class is 16 years and that of the girls is 15 years. The average age for the whole class is-

• 1] 15 years
• 2] 15.5 years
• 3] 16 years
• 4] Cannot be computed with the given information

After replacing an old member by a new member, it was found that the average age of five members of a club is the same as it was 3 years ago. What is the difference between the ages of the replaced and the new member?

• 1] 2 years
• 2] 4 years
• 3] 8 years
• 4] 15 years

There are 30 students in a class. The average age of first 10 students is 12.5 years. The average age of the remaining 20 students is 13.1 years. The average age (in years) of the students of the whole class is :

• 1] 12.5 years
• 2] 12.7 years
• 3] 12.8 years
• 4] 12.9 years

Find the average of all prime numbers between 30 and 50.

• 1]

  37.8

• 2]

  38.9

• 3]

  39.8

• 4]

  42.8

The average monthly salary of 660 workers in a factory is Rs. 380. The average monthly salary of officers is Rs. 2100 and the average monthly salary of the other workers is Rs. 340. Find the number of other workers.

• 1] 645
• 2] 650
• 3] 640
• 4] 642

Mukesh has twice as much money as Soham. Soham has 50% more money than Pankaj. If the average money with them is Rs. 110, then Mukesh has :

• 1] Rs. 155
• 2] Rs. 160
• 3] Rs. 180
• 4] Rs. 175

The average age of husband and his wife was 23 years at the time of their marriage. After five tears they have a one-year old child. The average age of the family of three, when the child was born, was-

• 1] 23 years
• 2] 24 years
• 3] 18 years
• 4] 20 years

The average of runs scored by a cricketer in his 99 innings is 99. How many runs will he have to score to his 100th innings so that his average of runs in 100 innings will become 100 ?

• 1] 100
• 2] 99
• 3] 199
• 4] 101

The average age of 30 students of a class is 14 years 4 months. After admission of 5 new students in the class the average becomes 13 years 9 months. The youngest one of the five new students is 9 years 11 months old. The average age of the remaining 4 new students is :

• 1] 10 years 4 months
• 2] 12 years 4 months
• 3] 11 years 2 months
• 4] 13 years 6 months