In a class there are 40 students and their mean marks are 80. If 20 students who have mean marks equal to 15, leave the class and after that 15 more student who have mean marks 30, admit in the class, find the new mean (approximate).
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95.71
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105.71
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125.52
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150.36
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None of these
A
Correct answer
Explanation
Initial total marks = 40 * 80 = 3200. After 20 students leave (sum = 20 * 15 = 300), remaining sum = 3200 - 300 = 2900. Remaining students = 20. After 15 students join (sum = 15 * 30 = 450), total sum = 2900 + 450 = 3350. Total students = 20 + 15 = 35. New mean = 3350 / 35 = 95.71.