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The average age of all the students o...

The average age of all the students of a class is 18 years. The average age of boys of the class is 20 years and that of the girls is 15 years. If the number of girls in the class is 20, then find the number of boys in the class. (a) 15          (b) 30         (c) 45         (d) 50

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RS AGGARWAL-AVERAGE-All Questions
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  3. The average age of all the students of a class is 18 years. The ave...

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  8. If the arithmetic mean of seventy-five numbers is calculated, it is...

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  9. The average of ten numbers is 7. If each number is multiplied by 12...

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  10. Average of ten positive numbers is barx . If each number is increased ...

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  11. The average height of 35 girls in a class was calculated as 160 cm....

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  12. The mean of 25 observations was found to be 78.4. But later on it w...

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  13. The average marks in Science subject of a class of 20 students is 6...

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  14. The average of 10 numbers is 40.2. Later it is found that two numbe...

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  15. A pupil’s marks were wrongly entered as 83 instead of 63. Due to th...

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  16. While calculating the average of a batsman as 36 in 100 matches tha...

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  17. The average age of seven boys sitting in a row facing North is 26 y...

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  18. The average of five numbers is 306.4. The average of the first two ...

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  19. The average marks obtained by 22 candidates in an examination is 45...

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  20. The average of 11 numbers is 10.9. If the average of the first six ...

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