AVERAGE

Important Formulas:  

1. Sum of first n natural numbers 

 

 2. Sum of the squares of first n natural numbers

 

3. Average of first n positive integers = 

4. Average of first n positive integers =  n+1


5. Average of first n odd integers =  n

Note: 0 is neither odd nor even 




PROBLEMS

1.  Find the sum of first 40 natural numbers

(a)800  (b) 810  (c)820  (d) 840  (e)none of these 

 Ans: (c)

2.  Find the average of first 10 multiples of 7

 (a)37.5  (b) 38.5  (c)39  (d)40  (e)none of these 

Ans: (b)

3. A batsman makes a score of 85 runs in the 16th match and thus increases his average by 2. Find his average after 16th match.

(a)55  (b) 57  (c)60  (d)62   (e)none of these

Ans:(a)

 





4. Average weight of 10 people increased by 1.5 kg when one person of 45 kg is replaced by a new man. Then weight of the new man is

 (a)50  (b) 55  (c)60  (d)65   (e)none of these

Ans: (c)
 
Total weight increased = 1.5*10 = 15
Weight of new person = 45+15 =60

PERCENTAGE

PERCENTAGE

1. What is 25% of 50% of 2/3 of 600?

(a)35  (b) 50  (c) 73  (d) 100 (e) none of these

Ans:  (b)

           

 2. The population of a town is126800. It increases by 15% in the 1st year & decreases by 20% in 

the second  year. What is the population of the town at the end of 2 years?

 (a)174984  (b) 135996  (c) 116656  (d) 145820 (e) none of these

Ans: (c)

 

 
3. In an examination it is required to get 40% of the aggregate marks to pass. A student gets 261 
marks and is declared failed by 4% marks. What are the maximum aggregate marks a student can 
get?

 (a)700  (b) 730  (c) 725  (d) 765 (e) none of these

   
4. Two candidates contested for an election. If one got 520 votes votes which was 65% of votes, 
what was the total no of votes?

 (a)858  (b) 800  (c) 780  (d) 754 (e) none of these


Ans: (b)

5. Kumar's salary is increased by 30% and subsequently decreased by 20%. The net effect is?

  (a)4% increase  (b) 10% increase  (c) 10% decrease (d)4% decrease (e) none of these

Ans: (d)

 

BLOOD RELATIONS

BLOOD RELATIONS

 

TYPE 1: “Pointing To” Method.

1. A man said to a women, “Your mother’s husband’s sister is my aunt”. How is the women related to the man?

(a) Grand Daughter  (b) Grandfather  (c) Husband  (d)  Father-in-law  (e) None of these

Ans: (d)

 2. Introducing Rajesh, Neha said, “His brother’s father is the only son of my grand father”. How Neha is related to Rajesh?

(a) Sister  (b) Daughter  (c) Mother  (d)  Niece  (e) None of these

Ans:(a)

 

3. A Man said to a woman. “Your brother’s only sister is my mother”. What is the relation of the woman with the maternal grandmother of that man?

(a) Mother  (b) Daughter  (c) Sister  (d)  Niece  (e) None of these

Ans: (a)

 

4. Pointing to a boy, Seema said “He is the son of my grandfather’s only child”. How Is the boy related to Seema?

(a)    Brother  (b) Cousin  (c) Sister  (d)  Data Inadequate  (e) None of these

Ans: (a)

 

5. Pointing to a photograph, a man said, “I have no brother or sister but that man’s father is my father’s son”, Whose photograph was it?

(a) His own  (b) His Son’s  (c) His father’s  (d) His nephew’s  (e) None of these

Ans: (b)

6. Pointing to a photograph, a lady tells Pramod, “I am the only daughter of this lady and her son is your maternal uncle”, How is the speaker related to Pramod’s father?

(a) Sister-in-law  (b) Wife (c) Neither (a) nor (b)  (d) Aunt  (e) None of these

Ans: (b)

 

7. Deepika tells Shraddha, “Your mother’s father’s son is the husband of my sister,” How is Deepika related to Shraddha?

(a) Sister-in-law  (b) Cousin (c) Aunt  (d) Data Inadequate  (e) None of these

Ans:  (c)