The average of 11 numbers is 30. If the average of first six

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   The average of 11 numbers is 30. If the | Solutions

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5. The average of 11 numbers is 30. If the average of first six numbers is 17.5 and that of last six is 42.5, then what is the sixth number?

1. A. 30           👈Correct Answer
2. B. 36
3. C. 45
4. D. 50

1. Answer & Explanation:

   Sum of 11 Number is 11 x 30 = 330

   
   

   Given : 

   
   

    [ Avg of first 6 numbers is 17.5, so Sum of first Six Number is 6 x 17.5 ]
   
    [ Avg of Last 6 numbers is 42.5, so Sum of last Six Number is 6 x 42.5 ]
   
   6th Number :  ( Sum of first Six Number + Sum of last Six Number ) - 330
   
   Hence the 6th Number is 30

1. Related Question on The Average of:

1. The average marks scored by Ganesh in English, Science, Mathematics and History is less than 15 from that scored by him in English, History, Geography and Mathematics. What is the difference of marks in Science and Geography secured by him?

1. A. 40
2. B. 50
3. C. 60
4. D. Data inadequate

1. Answer : C ( 60 )

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1. The average weight of three men A, B and C is 84 kg. D joins them and the average weight of the four becomes 80 kg. If E, whose weight is 3 kg more than that of D, replaces A, the average weight of B, C, D and E becomes 79 kg. The weight of A is

1. A. 65 kg
2. B. 70 kg
3. C. 75 kg
4. D. 80 kg

1. Answer : C ( 75 kg )

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1. In a class of 100 students the average marks obtained by a student in Maths is 44. If we remove the highest and the lowest the average of the class becomes 43.92. A total of three students get either highest or lowest. What is the average of these three students?

1. A. 73.33
2. B. 46.66
3. C. 59.99
4. D. cannot be determined

1. Answer : B ( 46.66 )

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1. Find the average of first 20 natural numbers ?

1. A. 6
2. B. 7.5
3. C. 10.5
4. D. 12

1. Answer : C ( 10.5 )

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1. The average of 8 men is increased by 2 years when 2 of them whose ages are 21 and 23 years as replaced by two new men. The average age of two new men is 

1. A. 22 years
2. B. 24 years
3. C. 28 years
4. D. 30 years

1. Answer : D ( 30 years )

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1. The average age of a class is 15.8 years. The average age of the boys in the class is 16.4 years and that of the girls is 15.4 years. What is the ratio of boys to girls in the class ?

1. A. 2 : 3
2. B. 2 : 4
3. C. 3 : 4
4. D. 3 : 5

1. Answer : A ( 2 : 3 )

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1. The average weight of 8 men is increased by 1.5 Kg when one of the men who weights 65 Kg is replaced by a new man. The weight of the new man is

1. A. 65 Kg
2. B. 77 Kg
3. C. 82 Kg
4. D. 90 Kg

1. Answer : B ( 77 Kg )

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1. A hiker walked for two days. On the second day, the hiker walked 2 hrs. longer and at an average speed of 1 km per hour faster than he walked on the first day. If during the two days he walked a total of 64 km and spent a total of 18 hrs. walking, what was his average speed on the first day?

1. A. 2 km/h
2. B. 3 km/h
3. C. 4 km/h
4. D. 5 km/h

1. Answer : B ( 3 km/h )

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1. The average age of 8 persons in a committee is increased by 2 years when two men aged 35 years and 45 years are substituted by two women. The average age of these two women is

1. A. 41 years
2. B. 45 years
3. C. 48 years
4. D. 53 years

1. Answer : C ( 48 years )

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1. Of the four numbers whose average is 60, the first is one-fourth of the sum of the last three. The first number is

1. A. 15
2. B. 45
3. C. 48
4. D. 25

1. Answer : C ( 48 )