Quiz Discussion

A student finds the average of 10 positive integers. Each integer contains two digits. By mistake, the boy interchanges the digits of one number say ba for ab. Due to this, the average becomes 1.8 less than the previous one. What was the difference of the two digits a and b?

• 1] 8
• 2] 6
• 3] 2
• 4] 4

There are five boxes in cargo hold. The weight of the first box is 200 kg and the weight of the second box is 20% higher than the weight of the third box, whose weight is 25% higher than the first box's weight. The fourth box at 350 kg is 30% lighter than the fifth box. Find the difference in the average weight of the four heaviest boxes and the four lightest boxes.

• 1] 51.5 kg
• 2] 75 kg
• 3] 37.5 kg
• 4] 112.5 kg
• 5] None of these

Ten years ago, the ages of the members of a joint family of eight people added up to 231 years. Three years later, one member died at the age of 60 years and a child was born during the same year. After another three years, one more member died, again at 60, and a child was born during the same year. The current average of this eight-member joint family is nearest to-

• 1] 21 years
• 2] 22 years
• 3] 23 years
• 4] 24 years
• 5] 25 years

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

The average of 25 results is 18. The average of first 12 of those is 14 and the average of last 12 is 17. What is the 13th result?

• 1] 74
• 2] 75
• 3] 69
• 4] 78

A shop of electronic goods is closed on Monday. The average daily sales for remaining six days of a week is Rs. 15,640 and the average sale of Tuesday to Saturday is Rs. 14,124. The sales on Sunday is -

• 1] Rs. 20,188
• 2] Data inadequate
• 3] Rs. 23,220
• 4] Rs. 21,704

Four years ago, the average age of A and B was 18 years. At present the average age of A, B, and C is 24 years. What would be the age of C after 8 years?

• 1] 25 years
• 2] 28 years
• 3] 32 years
• 4] 36 years

A school has only four classes that contain 10, 20, 30 and 40 students respectively. The pass percentage of these classes are 20%, 30%, 60% and 100% respectively. Find the pass % of the entire school.

• 1] 56%
• 2] 76%
• 3] 34%
• 4] 66%
• 5] None of these

The average of X1, X2 and X3 is 14. Twice the sum of X2 and X3 is 30. What is the value of X1?

• 1] 12
• 2] 16
• 3] 20
• 4] 27

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

• 1] 40
• 2] 39
• 3] 52
• 4] 55