Q:

A boy multiplied 987 by a certain number and obtained 559981 as his answer. If in the answer both 98 are wrong and the other digits are correct , then the correct answer would be :

A) 553681 B) 555181
C) 555681 D) 556581
 
Answer & Explanation Answer: C) 555681

Explanation:

987 = 3 * 7 * 47.
So, the required number must be divisible by each one of 3, 7, 47
553681 => (Sum of digits = 28, not divisible by 3)
555181 => (Sum of digits = 25, not divisible by 3)
555681 is divisible by each one of 3, 7, 47.

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14 7523
Q:

How many terms are in the G.P. 3, 6, 12, 24, ......., 384 ?

A) 8 B) 9
C) 10 D) 11
 
Answer & Explanation Answer: A) 8

Explanation:

Here a = 3 and r = 6/3 = 2. Let the number of terms be n.
Then, t = 384 => a * r^(n-1) = 384
=> 3 * 2^(n-1) = 384 => 2^(n-1) = 128 = 2^(7)

=> n-1 = 7 => n = 8.

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5 6437
Q:

The sum of the two numbers is 12 and their product is 35.What is the sum of the reciprocals of these numbers?

A) 12/35 B) 1/35
C) 35/8 D) 7/32
 
Answer & Explanation Answer: A) 12/35

Explanation:

Let a and b are the numbers.Then a+b is 12 and ab is 35.

 

a+b/ab = 12/35

 

1/b + 1/a = 12/35

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9 5993
Q:

 What is the greatest of 3 consecutive integers whose sum is 24 ?

A) 6 B) 7
C) 8 D) 9
 
Answer & Explanation Answer: D) 9

Explanation:

The sum of three consecutive integers can be written as n + (n + 1) + (n + 2) = 3n + 3

If the sum is 24, we need to solve the equation 3n + 3 = 24;

=> 3n = 21;

=> n = 7

The greatest of the three numbers is therefore 7 + 2 = 9

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11 5991
Q:

On dividing 2272 as well as 875 by 3-digit number N,we get the same remainder.The sum of the digits of N is:

A) 13 B) 12
C) 11 D) 10
 
Answer & Explanation Answer: D) 10

Explanation:

(2272-875) = 1397, is exactly divisible by N.

Now , 1397 = 11 x 127

The required 3-digit number is 127,the sum of digits is 10.

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12 5902
Q:

A number when divided by 779 gives a remainder 47. By dividing the same number by 19, what would be the remainder?

Answer

Number = ( 779 x a) + 47, where "a" is the quotient


           = (19 x 41 x a) + (19 x 2) + 9


           = 19 x (41a + 2) + 9


           = 19 x (New quotient) + 9


\inline \fn_jvn \therefore  Required remainder = 9

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8 5801
Q:

Which one of the following cannot be the square of a natural number?

A) 32761 B) 42437
C) 81225 D) 20164
 
Answer & Explanation Answer: B) 42437

Explanation:

The square of a natural number never ends in 7.
42437 is not the square of a natural number

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10 5463
Q:

If 60% of 35 of a number is 36, then the number is

A) 86 B) 94
C) 100 D) 115
 
Answer & Explanation Answer: C) 100

Explanation:

Let the number be x.Then

 

60% of 35of x=36.

 

=> 60100*35*x=36

 

=> 9x25=36 => x=25*369=100

 

Required number is 100.

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16 5445