Aptitude - Number System Online Quiz


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Following quiz provides Multiple Choice Questions (MCQs) related to Number System. 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 - 20 + 15 X 3.5 = ?

A - 72

B - 72.5

C - 62.5

D - none of these

Answer : B

Explanation

= 20 + 15 x 3.5
= 20 + 15 x (7/2)
= 20 + 52.5
= 72.5

Q 2 - If the number 3z4 is divisible by 6, then value of z =?

A - 0

B - 1

C - 6

D - 2

Answer : D

Explanation

6 = 3 x 2 i.e. divisible by 2
For divisibility: (3 + z + 4) must be divisible by 3
Therefore, z = 2

Q 3 - The difference of the squares of two consecutive even integers is divisible by which of the following integers?

A - 1

B - 5

C - 4

D - 2

Answer : C

Explanation

Let the consecutive integers(even) be 2p and (2p + 2):
= (2p + 2)2 - 2p2 = (2p + 2 + 2p)(2p + 2 -2p)
= 2(4p + 2)
= 4 (2p + 1)
Therefore, divisible by 4.

Q 4 - It is being given that (232) + 1) is completely divisible by a whole number. Which of the following numbers is completely divisible by this number?

A - 216 - 1

B - 216 + 1

C - 296 + 1

D - none of these

Answer : C

Explanation

Let 232 = p
-> (232 + 1) = p + 1
Let (p + 1) be completely divisible by natural number Z. Then->
(296 + 1) = [(232)3 + 1]
As (p3 + 1) = (p + 1)(p2 - p + 1), which is completely divisible by Z, since (p + 1) is completely divisible by Z.

Q 5 - 6 + 15 + 24 + 33 + ... + 123 = ?

A - 903

B - 603

C - 752

D - 690

Answer : A

Explanation

a = 6, d = 9, l = 123
Let number of terms be n
123 = a + (n - 1)d
123 = 6 + (n - 1)9
123 = 9n - 9
n = 14
Sn = n2 (a + l)
= 142 (6 + 123)
= 7 x 129
= 903

Q 6 - Which of the following number divides 325 + 326 + 327 + 328 completely?

A - 11

B - 16

C - 25

D - 30

Answer : D

Explanation

  325 + 326 + 327 + 328  = 324 x (31 + 32 + 33 + 34)  = 324 x (3 + 9 + 27 + 81)  = 460 x 120  which is divisible by 30.  

Q 7 - 5358 x 51 = y. What is y?

A - 273268

B - 273258

C - 273248

D - 273368

Answer : B

Explanation

  y =5358 x 51  =5358 x (50 + 1)  =5358 x 50 + 5358  =267900 + 5358  =273258  

Q 8 - 106 x 106 + 94 x 94 = y. What is y?

A - 20052

B - 20062

C - 20072

D - 20042

Answer : B

Explanation

  y = 106 x 106 + 94 x 94    = (106)2 + (94)2  = (100 + 6)2 + (100 -6)2  Using formulae (a+b)2 = a2 + b2 + 2ab and  (a-b)2 = a2 + b2 - 2ab  (a+b)2 + (a-b)2 = 2(a2 + b2)  ∴ y = 2 x [(100)2 + (6)2]  = 2 x [10000 + 36]  = 2 x 10036  = 20072  

Q 9 - a,b,c and d are consecutive odd number with average 42. What is the product of b and d?

A - 1860

B - 1890

C - 1845

D - 1677

Answer : C

Explanation

  let a = 2n + 1, b = 2n + 3, c = 2n + 5 and d = 2n + 7  Now (a + b + c + d) / 4 = 42  => (2n + 1 + 2n + 3 + 2n + 5 + 2n + 7) = 42 x 4  => 8n + 16 = 168  => n  = 152 / 8  => n = 19  ∴ b x d = (2 x 19 + 3) x (2 x 19 + 7)  = 41 x 45  = 1845  

Q 10 - One number is twice the second number and thrice the third number. If average of numbers is 44. What is the number?

A - 90

B - 99

C - 45

D - 36

Answer : B

Explanation

  Let's have smallest number be a  Thus (a + 2a + 3a) / 3 = 44  => 4a / 3 = 44  => a = 33  => largest number = 3a = 99  



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