Q:

Maheshwari wants to buy 7 floors in an 68 storied building whose numbering stars from 1 upto 68. But she has to follow certain rules which are as follows :

1) None of the floor should be a prime number

2) None of the digit of the floor should be a prime number

3) Maheshwari cannot buy the 1st floor as it is being assigned to the architect.

So how many options are left with Maheshwari to buy the floors ?

A) 11 B) 17
C) 13 D) 19
 
Answer & Explanation Answer: B) 17

Explanation:

Since floor starts form the 1 therefore 2 will be the 1st floor.
Form 1 to 10 only 4,6,8,9,10 are not prime.
Form 11 to 20 only 14 ,16,18 are not prime also non of their digits are prime.
From 21 to 30 each number has a prime number so it must no be consider.
In between 40 to 49 we have to consider only 40,44,46,48,49.
50 to 59 follow either of the condition so we have too neglect it.
In between 60 to 68 60,64,66,68.
total option = 17.

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4 4061
Q:

There is a 3 digited number. 3rd digit is the square root of the 1st digit. 2nd digit is the sum of 1st and 3rd. And that number is divisible by 2,3,6,7. What is that number?

A) 121 B) 943
C) 462 D) None
 
Answer & Explanation Answer: C) 462

Explanation:

Assume that the number is taken as XYZ.
Condition 1 => Z = sq.root(x) => Possible digits of X is 1,4,9
Condition 2 => Y = X + Z
X Y Z
1 2 1
4 6 2
9 12 3 => (wrong because it is 4 digit.)

and 121 is not divisible by 2

The answer is 462.

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3 4044
Q:

There are four consecutive even integers. Sum of the reciprocals of the first two number is (11/60). Find the reciprocal of third largest number of the series.

A) 1/12 B) 2/14
C) 1/14 D) 2/13
 
Answer & Explanation Answer: C) 1/14

Explanation:

Ans. C.
Let 4 consecutive even numbers are x, x+ 2, x+ 4, x+ 6
According to the question -
1/x + 1/x+2 = 11/60
x+2+x/ x(x+2) = 11/60
2(x+1)/x^2 + 2x = 11/60
120x + 120 = 11x 2 + 22x
11x 2 - 98x – 120 = 0
So ,
X = -24/22 , 10
X = -12/11 , 10
So, the numbers will be 10,12,14,16.
Hence,
Third largest number = 14
Reciprocal of third number = 1/14

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2 3951
Q:

Find the next number in the series 2, 3, 4, 8, 9, 10, 11, 16, 17, 18, 19, 20,...

A) 27 B) 26
C) 24 D) 25
 
Answer & Explanation Answer: B) 26

Explanation:

The pattern is three consecutive numbers and then three consecutive numbers missing.Then four consecutive numbers and then four consecutive numbers missing.Then five consecutive numbers and then five consecutive numbers missing.

 

The next number=20+6=26

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8 3912
Q:

If you write down all the numbers from 1 to 100, then how many times do you write 4 ?

A) 11 B) 20
C) 17 D) 14
 
Answer & Explanation Answer: B) 20

Explanation:

4, 14, 24, 34, 44, 54, 64, 74, 84, 94 => has 11 number of (4's)
40, 41, 42, 43, 45, 46, 47, 48, 49 => has 9 number of (4's)
So, totally (11 + 9 = 20) number of 4's in 1 to 100.

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2 3912
Q:

 7, 16, 36, 78, 144, ?

which number come in place of question mark

A) 168 B) 196
C) 222 D) 256
 
Answer & Explanation Answer: C) 222

Explanation:
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43 3560
Q:

How many prime numbers exist in 65×359×113 ?

A) 29 B) 31
C) 33 D) 27
 
Answer & Explanation Answer: B) 31

Explanation:

Given  65×359×113

2×35×5×79×113 

25×35×59×79×113

Thus, there are (5 + 5 + 9 + 9 + 3)= 31 prime numbers.

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5 3540
Q:

If 1/a+1/b+1/c = 1/(a+b+c) where a+b+c not equals '0', abc not equals '0', What is the value of (a+b) (b+c) (a+c) ?

A) 3 B) 2
C) 1 D) 0
 
Answer & Explanation Answer: D) 0

Explanation:

Let assume the value of a,b &c that will satisfy the equation.
so a=1,b=1,c= -1 or a=1,b= -1 &c=1 or a= -1,b=1,c=1
here all three cases satisfy the equation
assume any one a=1,b=1,c= -1

Hence (a+b)(b+c)(c+a)=(1+1)(1-1)(-1+1) = 0

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5 3493