A pupil's marks were wrongly entered as 83 instead of 63. Due to that the average marks for the class got increased by half (1/2). The number of pupils in the class is:

The average marks of 50 students in a class was found to be 64 . If the marks of two students were incorrectly entered as 38 and 42 instead of 83 and 24 , respectively, then what is the correct average?

Emily, a teacher, was calculating the test scores of her class, which consisted of 50 students. Initially, she calculated the class average to be 75. However, upon inspection, she discovered that scores 90 and 65 were mistakenly noted as 80 and 60. What is the correct class average (up to one decimal place) after rectifying these mistakes?

The mean and S.D. of marks of 70 students were found to be 65 and 5.2 respectively. Laterit was detected that the marks of one student was wrongly recorded as 85 instead of 58.Obtain the correct s.d

17) Two students appeared at an examination. One of them secured 9 marks more than the other and his marks was 56% of the sum of their marks. The marks obtained by them are:

If the average marks of two batches of 55 and 45 students respectively is 50 and 60, then the average marks of all the students is:a.54.5b.55c.56.8d.53