UPSC ONLINE ACADEMY

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Q.1 Average weight of 8 persons is increased by the 2.5kg when one of the weights 56kg is replaced by a new man. Find the weight of a new man ?

A) 76 kg

B) 77 kg

C) 78 kg

D) 79 kg

Ans. A

Shortcut:

Weight of new comer = Previous weight + No. of persons*Increase in average weight

Therefore, 56+8*2.5 = 76 kg

 

Q.2 Average age of 30 boys is equal to the 14yrs, when the age of the class teacher is included average becomes 15 years . Find the average of the class teacher ?

A) 45 yrs

B) 46 yrs

C) 47 yrs

D) 48 yrs

Ans. A

Shortcut:

Age of new comer = Previous age + No. of persons*Increase in average age

14+31(15-14)

=45 Ans.

 

Q.3 The average age of a group of 15 persons is 29 years. Among them, the age of each of the two persons is 55 years. What is the average age of remaining 13 persons?

A) 23

B) 28

C) 26

D) 25

Ans. D

15*29 = 435

2 person of 55kg leaving = 435-110

Therefore new average = 325/13 = 25

 

Q.4 A man spends his 2 months earning in 3 months & if he saves Rs. 1500 a year, then his monthly income is:

A) Rs. 450

B) Rs. 375

C) Rs. 425

D) Rs. 400

Ans. B

A man spends his 2 months earning in 3 months & if he saves Rs. 1500 a year, then his monthly income is:

Man saves one month’s earning in 3 months

Therefore he will save in one year salary of 4 months

But his saving in 1 year = Rs. 1500 His 4 month’s earning = Rs.1500

Therefore, His 1 month’s earning = Rs. 375

 

Q.5 The average score of a cricketer in certain number of innings is 15. When he scored a duck in one innings, his average dropped to 13.5. How many innings has he played in total, including the latest one?

A) 13

B) 10

C) 11

D) 9

Ans. B

Let the number of innings = x

Total runs scored by the player = 15x

New number of innings = x + 1

Also new average = = 13.5

? 15x = 13.5x + 13.5 ? 1.5x = 13.5 ? x = 9.

Number of innings played including the latest one = 9 + 1 = 10