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A student took an exam consisting of 5 subjects. In four of the subjects, he scored 90, 70, 75, and 65 marks. What should be the minimum and maximum marks in the fifth subject so that his overall average is at least 70 and at most 75?
- 55, 75
- 55, 70
- 50, 75
- 50, 70
Correct answer: 50, 75
Solution
Sum of the four known marks = 90+70+75+65 = 300. For an average between 70 and 75 over 5 subjects the total must be between 350 and 375, so the fifth mark lies between 350-300=50 and 375-300=75. Minimum 50, maximum 75.
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