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 - What is the 105th term of A.P. 4, 4.5, 5, 5.5 ... ?

A - 56

B - 55.5

C - 56.5

D - 55

Answer : A

Explanation

Here a = 4, d = 4.5 - 4 = 0.5, n = 105 
Using formula Tn = a + (n - 1)d 
T105 = 4 + (105 - 1) x 0.5 
= 56 

Q 2 - Which of the following is equal to 205x15?

A - 205x10+15x5

B - 200x15+5x15

C - 200(1+5)

D - 200+5x1x5

Answer : B

Explanation

  
205x15= (200+5) x15
=200x15+5x15  

Q 3 - How many digits are required to write numbers between 1 to 50?

A - 86

B - 91

C - 93

D - 49

Answer : B

Explanation

  
 1 to 9       ------ 9 digits  
 10 to 50   ------ 82 digits  

Q 4 - What is the greater of two numbers whose product is 1092 and the sum of the two numbers exceeds their difference by 42?

A - 48

B - 44

C - 52

D - 54

Answer : C

Explanation

  
 Let the numbers be x and y respectively.  
 According to question,       (x + y) - (x - y) = 42  
 or, y = 21  
 ∴x = 1092/21 = 52  
 Greater number is 52. 

Q 5 - If first term of an A.P. is 6, its common difference is 5 then what is its 11th term?

A - 5

B - 41

C - 46

D - 56

Answer : D

Explanation

 
 Here numbers are 14, 21, ..., 196 which is an A.P. 
 Here a = 6,  d = 5,    
 Using formula Tn = a + (n - 1)d    
 T11 = 6 + (11 - 1) x 5 = 56   

Q 6 - What is the sum of 1 + 2 + ... + 100 + 99 + ...1?

A - 200

B - 500

C - 1000

D - 10000

Answer : D

Explanation

 
 Given sequence = 2(1 + 2 + ... 99) + 100 
 Using formula Sn = (n/2)(a + l) 
 Required sum = 2 x (99/2)(1+99) +100 
 = 2 x 4950 + 100 
 = 9900 + 100 = 10000 

Q 7 - What is the 8th term of G.P. 2, 6, 18,...?

A - 2187

B - 6561

C - 4374

D - 6664

Answer : C

Explanation

  
 Here a = 2,  r = 3, n = 8. 
 Using formula Tn = arn- 1 
 Tn = 2 x 3(8-1)  
 =2 x 37  
 =2 x 2187  =4374 

Q 8 - One has to pay Rs 975 in yearly installments where each installment is less than earlier one by Rs 5. If first installment is of 100 in how many years, the entire amount will be paid?

A - 10

B - 12

C - 15

D - 25

Answer : C

Explanation

   
 Here a = 100, d = -5 , Sn = 975  
 Using formula Sn = (n/2)[2a + (n-1)d]  
 Sn = (n/2)[200 + (n-1)(-5)] = 975  
 => n(205 - 5n) = 1950  
 => 5n2 - 205n + 1950 = 0  
 => n2 - 41n + 390 = 0  
 => n2 - 26n - 15n + 390 = 0  
 => n(n-26) - 15(n-26)= 0  
 => (n-26)(n-15)  
 => n = 15 

Q 9 - If an A.P. have 4th term as 16 and 12th term as 80. What will be its common difference?

A - -10

B - -7

C - 8

D - 10

Answer : C

Explanation

  
 Let's have first term as a, common difference is d then  
 a + 3d = 15 ... (i)  
 a + 11d = 80 ... (ii)  
 Subtracting (i) from (ii)  
 => 8d = 64  
 => d = 8  

Q 10 - 142 + 152 ... + 502 = ?

A - 6738396

B - 6738416

C - 6738400

D - 6738406

Answer : D

Explanation

  
 Using formula  (12 + 32 ... +  n2) = [n(n+1)(2n+1)]/6  
 142 + 152 ... + 502 = (12 + 22 ... + 502) - (12 + 22 ... + 132)  
 = (50 x 51 x 101)/ 6 - (13 x 14 x 27) / 6  
 = 6739225 - 819  
 = 6738406 

aptitude_arithmetic.htm

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