Quiz Discussion

If the mean of 4 observations is 20, when a constant 'c' is added to each observation, the mean becomes 22. The value of c is :

• 1]

  6

• 2]

  -2

• 3]

  2

• 4]

  4

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 age of 40 students of class is 18 years. When 20 new students are admitted to the same class, the average age of the students of the class is increased by 6 months. The average age of newly admitted students is ?

• 1] 19 years
• 2] 19 years 6 months
• 3] 20 years
• 4] 20 years 6 months

Ajay working in a Cellular company as a salesman. His monthly salary is Rs. 200. But he gets bonus as per given rule. If he sells sim cards of Rs. X then his bonus will be   . In the first quarter of the year his average sale was Rs. 3000 per month. In the next 5 five month his average sale was Rs. 5000 per month and for next four month his average sale was Rs. 8000 per month. What is the average earning per month for the whole year?

• 1] Rs. 3350
• 2] Rs. 3610
• 3] Rs. 3750
• 4] Rs. 3560
• 5] None of these

The average weight of a group of 75 girls was calculated as 47 kgs. It was later discovered that the weight of one of the girls was read as 45 kgs. Whereas her actual weight was 25 kgs. What is the actual average weight of the group of 75 girls? ( Rounded off to two digits after decimal).

• 1] 34
• 2] 36
• 3] 30
• 4] None of these

David obtained 76, 65, 82, 67 and 85 marks (out of 100) in English, mathematics, physics, chemistry and biology. What are his average marks?

• 1] 65
• 2] 69
• 3] 75
• 4] None of these

The average of the first 100 positive integers is-

• 1] 49.5
• 2] 50.5
• 3] 51
• 4] 100

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 of the first five multiples of 3 is-

• 1] 3
• 2] 9
• 3] 12
• 4] 15

The average of five different positive numbers is 25. x is the decrease in the average when the smallest number among them is replaced by 0. What can be said about x?

• 1] x is less than 5
• 2] x is greater than 5
• 3] x is equal to 5
• 4] Cannot be determined