Average
- The average weight of 19 students is 15kg. by the admission of a new student the average weight is reduced to 14.8 kg. the weight of the new student is ?
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Weight of new student = Total weight of all 20 students - Total weight of initial 19 students
= (20 x 14.8 - 19 x 15) kgCorrect Option: C
Weight of new student = Total weight of all 20 students - Total weight of initial 19 students
= (20 x 14.8 - 19 x 15) kg
= 11 kg.
- The average weight of 8 persons is increased by 2.5 kg, when one of them whose weight is 56 kg is replaced by a new man. The weight of the man is ?
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Total Increase = 8 x 2.5 = 20 kg.
Correct Option: C
Total Increase = 8 x 2.5 = 20 kg.
weight of new man = (56 + 20) kg = 76 kg
- The average of the daily income of A, B and C is Rs . 60 . If B earns Rs . 20 more than C and A earns double of what C earns. What is the daily income of C ?
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Let C's earning = Rs. y.
Then, B's earning = Rs. (y + 20)
and A's earning = Rs. 2y
From question 2y + y + 20 + y= 3 x 60Correct Option: C
Let C's earning = Rs. y.
Then, B's earning = Rs. (y + 20)
and A's earning = Rs. 2y
∵ 2y + y + 20 + y= 3 x 60
⇒ 4x = 160
∴ x = 40
- The average age of an adult class is 40 years. 12 new students with an average age of 32 years join the class. Therefore decreasing the average by 4 year. what was the original strength of class ?
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Let original strength = y
Then , 40y + 12 x 32 = ( y + 12) x 36Correct Option: C
Let original strength = y
Then , 40y + 12 x 32 = ( y + 12) x 36
⇒ 40y + 384 = 36y + 432
⇒ 4y = 48
∴ y = 12
- In a class, there are 20 boys whose average age is decreased by 2 months, when one boy aged 18 years is replaced by a new boy. The age of the new boy is ?
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Total decrease
= ( 20 X 2 ) months
= 3 years 4 month
∴ Age of the new boy
= ( 18 years ) – ( 3 years 4 months)
Correct Option: A
Total decrease
= ( 20 X 2 ) months
= 3 years 4 month
∴ Age of the new boy
= ( 18 years ) – ( 3 years 4 months)
= 14 years 8 month