Aptitude - Questions & Answers

Aptitude - Arithmetic Online Quiz

Quiz

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.

Q 1 - What is the 105^th term of A.P. 4, 4.5, 5, 5.5 ... ?

Answer : A

Explanation

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

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

Answer : A

Explanation

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

Q 3 - The sum of first 99 natural numbers is?

Answer : D

Explanation

  
 Sum of n natural numbers is  S_n=n(n+1)/2  =99(99+1)/2  
 =4950

Q 4 - If the sum of four consecutive even numbers is 228, which is the smallest of the numbers?

Answer : B

Explanation

  
 According to the question:       
 x + x + 2 + x + 4 + x + 6 = 228  
 or, 4x + 12 = 228  
 or, x = 54  
 ∴The least even number is 54.

Q 5 - How many numbers between 10 and 200 are exactly divisible by 7?

Answer : D

Explanation

 
 Here numbers are 14, 21, ..., 196 which is an A.P. 
 Here a = 14,  d = 21 - 14 = 7,    
 Using formula T_n = a + (n - 1)d    
 T_n = 14 + (n - 1) x 7 = 196    
 => 7 - 7n = 196   
 => n = 189 / 7 = 27

Q 6 - How many odd numbered pages are present in a book of 1089 pages?

Answer : D

Explanation

 
 Here pages are 1, 3, ..., 1089 which is an A.P. Here a = 1,  d = 2, l = 1089    
 Using formula T_n = a + (n - 1)d 
 T_n = 1 + (n - 1) x 2 = 1089 
 => 2n -1 = 1089 
 => n = 1090 / 2 = 545

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

Answer : C

Explanation

  
 Here a = 2,  r = 3, n = 8. 
 Using formula T_n = ar^{n- 1} 
 T_n = 2 x 3^(8-1)  
 =2 x 3⁷  
 =2 x 2187  =4374

Q 8 - (1³ + 2³ ... + 15³) = ?

Answer : D

Explanation

  
 Using formula  (1³ + 2³ ... +  n³) = [(1/2)n(n+1]²  
 (1³ + 2³ ... + 15³) 
 = [(15 x 16)/2]²  
 = 120²  = 14400

Q 9 - If 1² + 2² ... + 10² = 385. What is 2² + 4² +... + 20²?

Answer : C

Explanation

   
 (2² + 4² ... + 20²)  = (1 x 2² + 2² x 2² + 3² x 2² +... +  10² x 2²)  
 = 2²(1² + 2² + .... + 10²) 
 = 4 x  385  
 = 1540

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

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

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