Quantitative Aptitude - Arithmetic Ability Questions

Q:

The probability of success of three students X, Y and Z in the one examination are 1/5, 1/4 and 1/3 respectively. Find the probability of success of at least two.

A) 1/4 B) 1/2
C) 1/6 D) 1/3
 
Answer & Explanation Answer: C) 1/6

Explanation:

P(X) = 15, P(Y) =14 , P(Z) = 13

 

Required probability:

 

= [ P(A)P(B){1−P(C)} ] + [ {1−P(A)}P(B)P(C) ] + [ P(A)P(C){1−P(B)} ] + P(A)P(B)P(C)

 

=14*13*45+34*13*15+23*14*15+14*13*15

 

460+360+260+160106016

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Filed Under: Probability

19 21084
Q:

Find the unit digit of 4198 + 612345 + 34866 + 2411 + 1.

A) 3 B) 2
C) 1 D) 0
 
Answer & Explanation Answer: C) 1

Explanation:

Given that, 4198+612345+34866+2411+1


Now Power Cycle of

4 is 4, 6 

6 is 6 

8 is 8, 4, 2, 6

1 is 1

 

4198- 198 is even number , So the unit digit value is 6 

 

612345 - It is always 6

 

34866-  66/4 the remainder is 2 , So the second value is 4

 

2411- 11 is odd number, So the unit digit value is 4

 

1 - It is always 1 


Total = 21

 

Therefore, The unit digit is 1

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Filed Under: Numbers
Exam Prep: CAT
Job Role: Bank PO

28 21076
Q:

If 18 bindres bind 900 books in 10 days , How many binders will be required to bind 660 books in 12 days?

A) 22 B) 14
C) 13 D) 11
 
Answer & Explanation Answer: D) 11

Explanation:

Let the required no of binders be X.

Less books , Less binders       (Direct Proportion)

More days, Less binders         (Indirect proportion)

 

 Books900:660Days12 : 10 18:x

Therefore, (900 * 12 * x) =  (660 * 10 * 18)  

=> x = 11

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Filed Under: Chain Rule

38 21054
Q:

The ratio of male and female in a city is 7 : 8 respectively and percentage of children among male and female is 25 and 20 respectively. If number of adult females is 156800, what is the total population of the city?

A) 4,12,480 B) 3,67,500
C) 5,44,700 D) 2,98,948
 
Answer & Explanation Answer: B) 3,67,500

Explanation:

Let the total population be 'p'

Given ratio of male and female in a city is 7 : 8

In that percentage of children among male and female is 25% and 20%

=> Adults male and female % = 75% & 80%

But given adult females is = 156800

=> 80%(8p/15) = 156800

=> 80 x 8p/15 x 100 = 156800

=> p = 156800 x 15 x 100/80 x 8

=> p = 367500

Therefore, the total population of the city = p = 367500

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Filed Under: Ratios and Proportions
Exam Prep: AIEEE , Bank Exams , CAT , GATE
Job Role: Bank Clerk , Bank PO

75 21052
Q:

The difference between Simple Interest and True Discount on a certain sum of money for 6 months at 1212% per annum is Rs 25. Find the sum.

A) Rs.6800 B) Rs.6500
C) Rs.6000 D) Rs.6200
 
Answer & Explanation Answer: A) Rs.6800

Explanation:

 

 

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Filed Under: True Discount

53 21018
Q:

When A, B and C are deployed for a task , A and B together do 70% of the work and B and C together do 50% of the work. who is most efficient?

A) A B) B
C) C D) can't be determined
 
Answer & Explanation Answer: A) A

Explanation:

A + B= 70%   

B + C =50%   

  (A+B)+(B+C)-(A+B+C)= B

=> B= 20%     A= 50%        and   C=30%

Hence A is most efficient

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Filed Under: Time and Work

31 20990
Q:

A room 5m 55cm long and 3m 74cm broad is to be paved with square tiles.Find the least number of square tiles required to cover the floor?

A) 156 B) 166
C) 176 D) 186
 
Answer & Explanation Answer: C) 176

Explanation:

Area of the room=(544 * 374)

 

size of largest square tile= H.C.F of 544 & 374 = 34 cm

 

Area of 1 tile = (34  x  34) cm2

 

Number of tiles required== [(544 x 374) / (34 x 34)] = 176

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Filed Under: Area
Exam Prep: Bank Exams
Job Role: Bank PO

54 20963
Q:

The least number which when divided by 5, 6 , 7 and 8 leaves a remainder 3, but when divided by 9 leaves no remainder, is:

A) 1677 B) 1683
C) 2523 D) 3363
 
Answer & Explanation Answer: B) 1683

Explanation:

L.C.M. of 5, 6, 7, 8 = 840.

 

 Required number is of the form 840k + 3

 

Least value of k for which (840k + 3) is divisible by 9 is k = 2.

 

 Required number = (840 x 2 + 3) = 1683.

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Filed Under: HCF and LCM

25 20955