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On mixing two classes of students having average marks 25 and 40 respectively, the overall average obtained is 30 marks. Find the number of students in first class, if the second class has 30 students. ?
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- 45
- 60
- 70
- 80
Correct Option: B
Students in the first class / Students in second class = (40 - 30)/(30 - 25) = 10/5 = 2/1
∴ Students in first class = 2 x 30 = 60
