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 y if 2y, y+10, 3y+2 are in an A.P.?

Answer : C

Explanation

    
As numbers are in A.P.  
Thus (y + 10) - 2y = (3y + 2) - (y + 10)  
=> 10 - y = 2y - 8  
=> -3y = -18  
=> y = 6

Q 2 - Find the number which being increased by 1 will be exactly divisible by 13, 15 and 19?

Answer : A

Explanation

  
LCM of 13, 15 and 19 is 3705  
So the desired number is3705-1=3704

Q 3 - (312x312+389x389+2x312x389) =?

Answer : C

Explanation

  
 By using a²+b²+2ab = (a + b)²  
 (312+389)²  =701²  
 =491401

Q 4 - The difference between 58% and 39% of a number is 247. What is 62% of that number?

Answer : B

Explanation

  
 Let the number be y.  
 According to question,       (58 - 39)% of y = 247  
 Or, y x (19/100) = 247  
 Or, y = 1300  
 ∴62% of 1300 = (62/100) x 1300 = 806

Q 5 - The number obtained by interchanging the digits of a two digit number is less than the original number by 18. If sum of the digits is 6, what was the original two digit number?

Answer : C

Explanation

  
 Let the original number be 10x + y.  
 Number obtained by interchanging the digits = 10y + x  
 ∴ (10x + y) - (10y + x) = 18  
 Or, x - y = 2 ... (i)  
 Also, x + y = 6 ... (ii)  
 From equations (i) and (ii), 
 x = 4 and y = 2.  
 ∴ Original number = (10 x 4) + 2 = 42

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 - If a ≠ b then which of the following statement is correct?

Answer : C

Explanation

For any two unequal number a and b, arithmetic mean is always greater than their geometric mean. ∴ c is the correct answer.

Q 8 - One has to pay 3600 in 40 installments which are in A.P. After 30th installment being paid, amount left will be one third. What will be the 8^th installment?

Answer : C

Explanation

   
 Installments = 40, Total debt = 3600  Installments = 30, 
 Total debt = (2/3) x 3600 = 2400  
 Let the installments be a, a + d, a + 2d, ...  
 Using formula S_n = (n/2)[2a+(n-1)d]   
 S₃₀ = (30/2)[2a+(30-1)d] = 3600  
 => 2a + 29d = 160 ... (i)  
 S₄₀ = (40/2)[2a+(40-1)d] = 2400  
 => 2a + 39d = 180 ... (ii)  
 Subtracting (i) from (ii)  
 => 10d = 20  
 => d = 2  
 Using (i)  2a = 160 - 29d = 160 - 58 = 102  
 => a = 51  
 Using formula T_n = a + (n-1)d  
 ∴ T₈ = 51 + 7 x 2 = 51 + 14  = 65

Q 9 - (1³ + 2³ ... + 15³) - (1 + 2 + ... + 15)= ?

Answer : C

Explanation

  
 Using formula  (1³ + 2³ ... +  n³) = [(1/2)n(n+1]²  
 (1³ + 2³ ... + 15³) = [(15 x 16)/2]²  
 = 120²  = 14400  
 Using formula  (1 + 2 + ... n) = [(1/2)n(n+1]  
 ∴ (1³ + 2³ ... + 15³) - (1 + 2 + ... + 15) 
 = 14400 - (1/2) x 15 x 16 = 14400 - 120  
 = 14280

Q 10 - Suman purchases N.S.C. every year whose value exceed s previous year's N.S.C by 500 Rs. In 10 years, she has bought N.S.Cs of 50000 Rs. What was the value of N.S.C. she bought in first year?

Answer : D

Explanation

   
 Let the required amount is a.  
 Also, d = 500, n = 10, S₁₀ = 50000  
 Using formula S₁₀ = (n/2)[2a + (n-1)d  
 => (10/2)[2a + (10-1)500] = 50000  
 => 5(2a + 9 x 500) = 50000  
 => 2a + 4500 = 10000  
 => a = 5500 / 2 = 2750

aptitude_arithmetic.htm

Print Page