Average, General Mathematics

Question: The average age of `30`students is `9` years. If the age of thier teacher is inclued,it becomes `10` years .The age of the teacher (in years) is :
A
`27`

B
`3`

C
`35`

D
`40`

Note: Age of the teacher `= (31 xx 10 + 30 xx 9)` `= 40 years`
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Question: The average age of `24` boys and the teacher is `15` years. when the teacher,s age is excluded, the average decreases by `1`.What is the age of the teacher ?
A
`38 years`

B
`39 years`

C
`40 years`

D
Data inadequate

Note: Age of the teacher `= (25 xx 15 - 24 xx 14)` `= 39 years`
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Question: The average wieght of `50` balls is `2`lbs.If the wieght of the container be included, the average wieght will increase by `0.05` lbs.The wieght of the container is :
A
`4.55 lbs`

B
`2.2 lbs`

C
`2.3 lbs`

D
`2.5 lbs`

Note: Weight of the container `= (51 xx 2.05 - 50 xx 2) lbs`. `= (104.55 - 100) lbs -` `= 4.55 lbs`.
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Question: The average weight of `29` students is `28` kg. By the admission of a new student,the average weight is resuced to `27.8 kg.The weight of the new student is :
A
`22 kg`

B
`21.6 kg`

C
`22.4 kg`

D
`21 kg`

Note: Weight of the new student `= (3 xx 27.8 - 29 xx 28) kg` `= 22 kg`.
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Question: The average selary per month of `30` employees in a company is Rs `4000`. If the manager,s salary is added, the average salary incrses to Rs`4300, what is the salary of the manager ?
A
`Rs 10000`

B
`Rs 13000`

C
`Rs 12000`

D
`Rs 13300`

Note: Salary of the manager `= Rs (31 xx 4300 - 30 xx 4000)` `= Rs 13300`.
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Question: The average weight of `8`men is increassed by `1.5 kg `when one of the men who weight `65`kg is replaced by anew men .The weight of e new man is :
A
`76 kg`

B
`76.5 kg`

C
`76.7 kg`

D
`77 kg`

Note: Total weight increased `= (8 xx 1.5) kg` `= 12 kg` Weight of new man `= (65 + 12) kg` `= 77 kg`
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Question: The average weight of `9`mangoes increases by `20` g if one of them weighting `120`g is replaced by anpther.The weight of the new mango is :
A
`180 g`

B
`200 g`

C
`260 g`

D
`300 g`

Note: Total weight increased `= (9 xx 20) gm` `= 180 gm` Weight of new mango `(120 + 180) gm` `= 300 gm`
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Question: The average weight of `6` men decreases by `3` kg when one of them weighting `80` kg is replaced by a new man. The weight of new man is :
A
`56 kg`

B
`58 kg`

C
`62 kg`

D
`76 kg`

Note: Total weight decreased `=(6 xx 3) kg` `= 18 kg` weight of new man `= (80 - 18) kg` `= 62 kg`
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Question: The average of `5` consecutive numbers is n.If next two number are also included, the average will
A
increase by `1`

B
remain the same

C
increase by `1.4`

D
increase by `2`

Note: Let five consecutive numbers be x,x + 1,x + 2,x + 3, & x + 4. Their average `= (5x + 10)/5` `= (x + 2)`. Average of `7` numbers `= (5x + 10) + (x + 5) + (x + 6)/7` `= (x + 3)`. So, the average increased by `1`.
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Question: The average age of a commitiee of eight members is `40` years. A member aged `55` years retired and his place was taken by another member aged `39` years .The average age of the present committee is :
A
`39 years`

B
`38 years`

C
`36 years`

D
`35 years`

Note: Required average `= ((8 xx 40 - 55 + 39)/8)` `= 304/8` `= 38 years`
1. Report

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Question: The average age of `30`students is `9` years. If the age of thier teacher is inclued,it becomes `10` years .The age of the teacher (in years) is :

Question: The average age of `24` boys and the teacher is `15` years. when the teacher,s age is excluded, the average decreases by `1`.What is the age of the teacher ?

Question: The average wieght of `50` balls is `2`lbs.If the wieght of the container be included, the average wieght will increase by `0.05` lbs.The wieght of the container is :

Question: The average weight of `29` students is `28` kg. By the admission of a new student,the average weight is resuced to `27.8 kg.The weight of the new student is :

Question: The average selary per month of `30` employees in a company is Rs `4000`. If the manager,s salary is added, the average salary incrses to Rs`4300, what is the salary of the manager ?

Question: The average weight of `8`men is increassed by `1.5 kg `when one of the men who weight `65`kg is replaced by anew men .The weight of e new man is :

Question: The average weight of `9`mangoes increases by `20` g if one of them weighting `120`g is replaced by anpther.The weight of the new mango is :

Question: The average weight of `6` men decreases by `3` kg when one of them weighting `80` kg is replaced by a new man. The weight of new man is :

Question: The average of `5` consecutive numbers is n.If next two number are also included, the average will

Question: The average age of a commitiee of eight members is `40` years. A member aged `55` years retired and his place was taken by another member aged `39` years .The average age of the present committee is :