Aptitude - Arithmetic Online Quiz


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Following quiz provides Multiple Choice Questions (MCQs) related to Basic Arithmetic. You will have to read all the given answers and click over the correct answer. If you are not sure about the answer then you can check the answer using Show Answer button. You can use Next Quiz button to check new set of questions in the quiz.

Questions and Answers

Q 1 - Which term of 2,7, 12,17... is 87?

A - 16th

B - 17th

C - 18th

D - 15th

Answer : C

Explanation

  
Here a = 2,  d = 7 - 2 = 5,  
Let there be n term.  
Using formula Tn = a + (n - 1)d  
Tn = 2 + (n - 1) x 5 = 87  
=> 5n - 3 = 87  
=> n = 18 

Q 2 - Which number should be replaced by Y in [Y/81][Y/36]=1?

A - 54

B - 64

C - 24

D - 96

Answer : A

Explanation

  
[Y/81][ Y/36]=1  
=> Y2=81x36  
=> Y = √ 81x36  =54  

Q 3 - The least prime number is?

A - 3

B - 2

C - 1

D - 0

Answer : B

Explanation

2 is the least prime number.

Q 4 - The product of two successive positive integers is 462. Which is the smaller integer?

A - 20

B - 22

C - 21

D - 23

Answer : C

Explanation

  
 Suppose the two consecutive integers be y and y + 1 respectively.  According to question,       
 (y) x (y + 1) = 462  
 Or, y2 + y - 462 = 0  
 Or, y2 + 22y - 21y - 462 = 0  
 Or, y(y + 22) - 21(y + 22) = 0  
 Or, (y + 22) (y - 21) = 0  
 Or, y = 21 

Q 5 - The average of four consecutive even numbers is one- fourth of the sum of these numbers. What is the difference between the first and the last number?

A - 4

B - 6

C - 2

D - 1

Answer : B

Explanation

  
 Let the four consecutive even numbers are x, x + 2, x + 4 and x + 6.  
 ∴ Required difference = x + 6 - x = 6 

Q 6 - What is the sum of first 20 odd numbers?

A - 210

B - 300

C - 400

D - 420

Answer : C

Explanation

 
 Here numbers are 1, 3, ..., upto 20 terms which is an A.P. Here a = 1,  d = 2, n = 20. 
 Now Using formula Sn = (n/2)[2a + (n-1)d]  
 ∴ Required sum = (20/2)[2+(20-1)x2]  = 10 x 40  = 400 

Q 7 - Sum of how many terms of series 3, 9, 27 will be 363?

A - 5

B - 6

C - 7

D - 8

Answer : A

Explanation

   
 Here a = 3, r = 3 , Sn = 363  
 Using formula Sn = a(rn - 1) / (r-1)  
 Sn = 3 x (3n - 1) / (3 - 1) = 363  
 => 3n - 1 = (363 x 2) / 3  
 => 3n = 243 
 = 35  
 => n = 5 

Q 8 - If population of a bacteria doubles every 2 minutes. In how much minutes, it will grow from 1000 to 512000?

A - 10

B - 12

C - 14

D - 18

Answer : D

Explanation

   
 Let the required growth be 1000, 2000, 4000,...512000.  
 Here, a = 1000, r = 2, Tn = 512000  
 Using formula Tn = arn-1 
 => 1000 x 2n-1 = 512000  
 => 2n-1 = 512 = 29  
 => n - 1 = 9  => n = 10 
 ∴ time taken will be 2 x 9 = 18 minutes. 

Q 9 - What is the 18th term of A.P. 3, 5, 7, 9 ...?

A - 50

B - 52

C - 35

D - 37

Answer : D

Explanation

 
 Here a = 3, d = 5 - 3 = 2, n = 18 
 Using formula Tn = a + (n - 1)d 
 T18 = 3 + (18 - 1) x 2 
 = 37 

Q 10 - (13 + 23 ... + 203) - (1 + 2 + ... + 20)= ?

A - 43950

B - 43970

C - 43980

D - 43960

Answer : C

Explanation

  
 Using formula  (13 + 23 ... +  n3) = [(1/2)n(n+1]2  
 (13 + 23 ... + 203) = [(20 x 21)/2]2  = 2102  = 44100  
 Using formula  (1 + 2 + ... n) = [(1/2)n(n+1]  
 ∴ (13 + 23 ... + 153) - (1 + 2 + ... + 15) = 44100 - (1/2) x 15 x 16 
 = 44100 - 120  
 = 43980 

aptitude_arithmetic.htm

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