Quiz Discussion

The average of the first 100 positive integers is-

• 1] 49.5
• 2] 50.5
• 3] 51
• 4] 100

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 price of 10 books is Rs.12 while the average price of 8 of these books is Rs.11.75. Of the remaining two books, if the price of one book is 60% more than the price of the other, what is the price of each of these two books?

• 1] Rs. 5, Rs.7.50
• 2] Rs. 8, Rs. 12
• 3] Rs. 16, Rs. 10
• 4] Rs. 12, Rs. 14

The average weight of 21 boys was recorded as 64 kg. If the weight of the teacher was added, the average increased by 1 kg. What was the teacher’s weight?

• 1] 86 kg
• 2] 64 kg
• 3] 72 kg
• 4] 84 kg

The mean of 25 observations was found to be 78.4. But later on it was found that 96 were misread as 69. The correct means is-

• 1] 76.54
• 2] 78.4
• 3] 79.48
• 4] 81.32

A train covers the first 16 km at a speed of 20 km per hour another 20 km at 40 km per hour and the last 10 km at 15 km per hour. Find the average speed for the entire journey.

• 1]

  24 km

• 2]

  26 km

• 3]

  21 km

• 4]

  km

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

If the average of 5 consecutive integers is x then, find the average of next to next 5 consecutive integers.

• 1] x + 5
• 2] x - 5
• 3] x + 10
• 4] x + 25

The mean weight of 100 students in a class is 46 kg. The mean weight of boys is 50 and of girls is 40 kg. Therefore, the number of boys is:

• 1] 50
• 2] 60
• 3] 70
• 4] 65

Average of 80 numbers are 42. When 5 more numbers are included, the average of 85 numbers become 45. Find the average of 5 numbers.

• 1] 82
• 2] 89
• 3] 93
• 4] 98