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Q:

# In a two-digit number, the digit in the unit's place is more than twice the digit in ten's place by 1. If the digits in the unit's place and the ten's place are interchanged,difference between the newly formed number and the oiginal number is less than the original number by 1. What is the original number ?

 A) 35 B) 36 C) 37 D) 39

Answer:   C) 37

Explanation:

Let the ten's digit be x. Then, unit's digit = 2x + 1.

[10x + (2x + 1)] - [{10 (2x + 1) + x} - {10x + (2x + 1)}] = 1

<=> (12x + 1) - (9x + 9) = 1 <=> 3x = 9, x =  3.

So, ten's digit = 3 and unit's digit = 7. Hence, original number = 37.

Q:

What is the common ratio of the following geometric sequence?

4, 2, 1, 0.5, 0.25, 0.125,...

 A) 0.5 B) -1 C) 1.5 D) -0.5

Answer & Explanation Answer: A) 0.5

Explanation:

In mathematics, a geometric progression, also known as a geometric sequence, is a sequence of numbers where each term after the first is found by multiplying the previous one by a fixed, non-zero number called the common ratio.

Herein the given sequence, 4, 2, 1, 0.5, 0.25, 0.125,...

Common Ratio r = 2/4 = 1/2 = 0.5/1 = 0.25/0.5 = 0.125/0.25 == 0.5.

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0 70
Q:

What is the place value of 6 in 64?

 A) 6 B) 60 C) 64 D) 10

Answer & Explanation Answer: B) 60

Explanation:

We know that,

● Each digit has a fixed position called its place.

● Each digit has a value depending on its place called the place value of the digit.

● The face value of a digit for any place in the given number is the value of the digit itself

● Place value of a digit = (face value of the digit) × (value of the place).

Hence, the place value of 6 in 64 = 6 x 10 = 60.

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5 578
Q:

Which one of the following is not a prime number?

 A) 91 B) 71 C) 41 D) 31

Answer & Explanation Answer: A) 91

Explanation:

Prime Numbers :: Numbers which are divisible by only 1 and itself are Prime Numbers.

It's answer will be 91.

Because 91 can be divisible by 7,13,91,1.

It is quite clear that prime number should be divisible only by itself and by 1.

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5 479
Q:

There are 5 consecutive odd numbers. If the difference between square of the average of first two odd number and the of the average last two odd numbers is 396, what is the smallest odd number?

 A) 29 B) 27 C) 31 D) 33

Answer & Explanation Answer: A) 29

Explanation:

Let the five consecutive odd numbers be x-4, x-2, x, x+2, x+4

According to the question,

Difference between square of the average of first two odd number and the of the average last

two odd numbers is 396

i.e, x+3 and x-3

Hence, the smallest odd number is 33 - 4 = 29.

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4 498
Q:

What are the Multiples of 6 and the Common Multiples of 4 and 6?

 A) 12, 34, 42 B) 12, 18, 36, C) 6, 4, 14 D) 4, 8, 16

Answer & Explanation Answer: B) 12, 18, 36,

Explanation:

The Multiples of 6 are 6, 12, 18, 24, 30, 36, 42, 48, 54, 60.

The Multiples of 4 are 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, 60.

The Common Multiples of 4 & 6 upto 60 numbers are given as 12, 24, 36, 48, 60.

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8 473
Q:

12 students of class IX took part in GK quiz. If the number of boys is 4 more than the number of girls. Find the number of boys and girls took part in the quiz ?

 A) 7, 5 B) 9, 3 C) 8, 4 D) 6, 6

Answer & Explanation Answer: C) 8, 4

Explanation:

Let the number of girls = x

=> x + x + 4 = 12

=> 2x = 8

=> x = 4

=> Number of girls = 4

=> Number of boys = 4 + 4 = 8

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14 574
Q:

A number is 2 more than thrice the second number and 4 times the smaller number is 5 more than the greater number. What is greater number  ?

 A) 7 B) 23 C) 9 D) 21

Answer & Explanation Answer: B) 23

Explanation:

Let the greater and smaller number be p and q respectively.

4q = p + 5 ------ (I)

p = 3q+2 ------- (II)

From equation (I) and (II)

q = 7

p = 23

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8 738
Q:

What will be added to the unit digits of the number 86236 so that number will be divisible by 9  ?

 A) 1 B) 2 C) 3 D) 0

Answer & Explanation Answer: B) 2

Explanation:

A number is divisible by 9 only if the sum of the digits of the number is divisible by 9.

Here 86236 = 8 + 6 + 2 + 3 + 6 = 25

We must add 2 to 25 to become 27 which is divisible by 9.

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4 1083