The mean of 50 observations was 36. It was found later that an observation 48 was wrongly taken as 23. The corrected new mean is___________?

Related Mcqs:

1. The average of 18 observations was calculated and it was 124. Later on it was discovered that two observations 46 and 82 were incorrect. The correct values are 64 and 28. The correct average of 18 observations is___________?

   A. 123
   B. 137
   C. 121
   D. 122

2. The arithmetic mean of the scores of a group of students in a test was 52. The brightest 20% of them secured a mean score of 80 and the dullest 25% a mean score of 31. The mean score of remaining 55% is___________?

   A. 45
   B. 50
   C. 51.4 approx.
   D. 54.6 approx.

3. The mean marks of 30 students in a class is 58.5. Later on it was found that 75 was wrongly recorded as 57. Find the correct them.

   A. 57.4
   B. 57.5
   C. 58.9
   D. 59.1

4. The average of 9 observations was 9, that of the 1st of 5 being 10 and that of the last 5 being 8. What was the 5th observation?

   A. 9
   B. 8
   C. 7
   D. 6

5. If the arithmetic mean of seventy five numbers is calculated, it is 35. If each number is increased by 5, then mean of new number is___________?

   A. 30
   B. 40
   C. 70
   D. 90

6. The average height of 35 boys in a class was calculated as 180cm. It has later found that the height of one of the boys in the class was wrongly written as 166 cm whereas his actual height was 106 cm. Find the actual average height of the boys in the class (Round off your answer to two decimal places)?

   A. 179.29 cm
   B. 178.29 cm
   C. 179.38 cm
   D. 178.39 cm

7. A pupil’s marks were wrongly entered as 83 instead of 63. Due to the average marks for the class got increased by half. The number of pupils in the class is___________?

   A. 10
   B. 20
   C. 40
   D. 73

8. The time taken by a man to row his boat upstream is twice the time taken by him to row the same distance downstream. If the speed of the boat in still water is 42 kmph, find the speed of the stream?

   A. 12 kmph
   B. 13 kmph
   C. 14 kmph
   D. 15 kmph

9. Two pipes A and B together can fill a cistern in 4 hours. Had they been opened separately, then B would have taken 6 hours more than A to fill cistern. How much time will be taken by A to fill the cistern separately?

   A. 1 hr
   B. 2 hrs
   C. 6 hrs
   D. 8 hrs

10. A rectangular field 30 m long and 20 m broad. How much deep it should be dug so that from the earth taken out, a platform can be formed which is 8 m long, 5.5 m broad and 1.5 m high where as the earth taken out is increase by 10/5?

    A. 12 cm
    B. 10 cm
    C. 18 cm
    D. 24 cm