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Knowing Numbers

Description: This test covers concepts of Numbers
Number of Questions: 15
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Tags: knowing our numbers Numbers Knowing Numbers
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What is the largest three-digit number that can be formed by the digits 3, 6, 8, and 7 such that the digits are not repeated?

  1. 837

  2. 863

  3. 873

  4. 836

  5. 876


Correct Option: E
Explanation:

The given digits are 3, 6, 8 and 7. Here, 3 < 6 < 7 < 8 In order to form the largest three-digit number, we have to place digits 8, 7, and 6 at the hundreds, tens, and ones place, respectively. Thus, the required largest three-digit number is 876. Hence, the correct option is (5).

Which number is equivalent to the expansion 8 x 10000000 + 8 x 1000000 + 1 x 100000 + 4 x 10000 + 2 x 100 + 1 x 1?

  1. 8,81,40,201

  2. 8,81,42,010

  3. 88,14,00,201

  4. 8,81,421

  5. 88,14,210


Correct Option: A
Explanation:

The given expansion is 8 x 10000000 + 8 x1000000 + 1 x 100000 + 4 x 10000 + 2 x 100 + 1 x1 = 8 crores + 8 ten lakhs + 1 lakh + 4 ten thousands + 2 hundreds + 1 ones = 88140201 Thus, the number 88140201is equivalent to the given expansion. Hence, option (1) is correct.

What is the approximate sum of the numbers 9,38,278 and 62,499?

  1. 20,00,000

  2. 21,00,000

  3. 11,00,000

  4. 15,00,000

  5. 10,00,000


Correct Option: E
Explanation:

The two given numbers are 9,38,278 and 62,499. The number 9,38,278 can be rounded-off to the nearest ten thousands as 9,40,000.

Similarly, the number 62,499 can be rounded-off to the nearest ten thousands as 60,000. Thus, the approximated sum of the numbers 9,38,278 and 62,499 can be calculated by adding the numbers 9,40,000 and 60,000. 9,40,000 + 60,000 = 10,00,000 The correct answer is  option (5). 

The numbers 2627, 8612, 8126, and 3716 can be arranged in the descending order as

  1. 2627 > 8612 > 8126 > 3716

  2. 2627 > 3716 > 8126 > 8612

  3. 8612 > 8126 > 3716 >2627

  4. 8612 > 3716 > 8126 > 2627

  5. 2627 > 3716 > 8612 > 8126


Correct Option: C
Explanation:

The given numbers are 2627, 8612, 8126 and 3716. When a set of numbers is arranged in descending order, the numbers are written in such a manner that the greatest number is placed at the beginning of the sequence; the second greatest number is placed after that and so on. The given numbers can be arranged in descending order as 8612 > 8126 > 3716 > 2627. Hence, option (3) is correct. 

What is the difference between the greatest and smallest four-digit numbers that can be formed by the digits 6, 4, 5, and 9 such that the digit 6 is always at the ones place and no digit is repeated?

  1. 2590

  2. 3586

  3. 5496

  4. 4950

  5. 3950


Correct Option: D
Explanation:

The given digits are 6, 4, 5, and 9. Here, 4 < 5 < 6 < 9 We have to form a four-digit number such that digit 6 is always at the ones place. In order to form the greatest four-digit number, we have to place digits 9, 5, and 4 at the thousands, hundreds and tens place respectively and 6 at the ones place.  Therefore, the number so formed is 9546. Similarly, the smallest four-digit number will have 4 at the thousands place, 5 at the hundreds place, 9 at the tens place, and 6 at the ones place. The number so formed is 4596. Therefore, the smallest and the greatest numbers that can be formed by the digits 6, 4, 5 and 9 such that digit 6 is always at the ones place and no digit is repeated are 4596 and 9546, respectively. Hence, the required difference is 9546 - 4596 = 4950 The correct option is (4). 

Prakash's monthly salary is Rs. 16,180, out of which he saves Rs. 8,870. What is his approximate monthly expenditure?

  1. Rs. 5,000

  2. Rs. 8,000

  3. Rs. 6,000

  4. Rs. 7,000

  5. Rs. 4,000


Correct Option: D
Explanation:

Prakash's monthly salary is Rs. 16,180. His monthly saving = Rs. 8,870  The numbers 16,180 and 8,870 can be rounded off to the nearest thousands as 16,000 and 9000, respectively. Thus, Prakash's approximate monthly expenditure is  = Rs. 16,000 - Rs. 9000 = Rs. 7,000 The correct answer is option (4).

Ramu, who is a toy-seller, earns Rs. 12,400 in a month. How much money does he earn in a year?

  1. Rs. 1,40,400

  2. Rs. 1,60,800

  3. Rs. 1,48,800

  4. Rs. 1,48,808

  5. Rs. 1,70,820


Correct Option: C
Explanation:

Amount of money Ramu earns in a month = Rs. 12,400 Number of months in a year = 12 Therefore, the amount of money Ramu earns in a year can be 12,400 * 12 = Rs. 1,48,800 Thus, Ramu earns Rs. 1,48,800 in a year. Hence, option (3) is correct. 

What is the value of the expression {(30 + 45) / 5} + {(18 - 3) x 20}?

  1. 315

  2. 215

  3. 105

  4. 115

  5. 415


Correct Option: A
Explanation:

The expression {(30 + 45) / 5} + {(18 - 3) x 20} can be solved by simplifying the brackets. {(30 + 45) / 5} + {(18 - 3) x 20} = {75 / 5} + {15 x 20} = 15 + 300 = 315  Hence, the value of the given expression is 315. The correct answer is option (1). 

Until May, Radhika's monthly salary was Rs. 13,500. In the month of June, her salary increases by Rs. 2,150. What is her current monthly salary?

  1. Rs. 13,750

  2. Rs. 15,650

  3. Rs. 14,300

  4. Rs. 14,650

  5. Rs. 15,560


Correct Option: B
Explanation:

Radhika's monthly salary in May = Rs. 13,500. 

Increase in salary = Rs. 2,150

Therefore, her current monthly salary can be obtained by adding Rs. 2,150 to Rs. 13,500.

Thus, her current monthly salary is Rs. 15,650.

The correct answer is option (2). 

Which of the following pairs represents the same weight?

  1. 50 kg and 500 g

  2. 50 kg and 5000 g

  3. 8 kg and 8000 g

  4. 9 kg and 900 g

  5. 6 kg and 60000 g


Correct Option: C
Explanation:

It is known that 1 kg = 1000 g Therefore, 50 kg = 50 * 1000 g = 50,000 g  8 kg = 8 * 1000 g   = 8000 g 6 kg = 6 * 1000 g = 6000 g  9 kg = 9 * 1000 g = 9000 g Therefore, the correct answer is option (3).

The sum of the Roman numerals LVI and XCIV can be written in Hindu-Arabic numerals as

  1. 110

  2. 120

  3. 150

  4. 160

  5. 170


Correct Option: C
Explanation:

The given Roman numerals are LVI and XCIV. LVI = L + VI = 50 + 6  [L = 50; VI = 6] = 56 XCIV = XC + IV = (100 - 10) + 4  [X = 10; C = 100; IV = 4] = 94 Therefore, LVI + XCIV = 56 + 94  = 150 The correct answer is option (3).

Priya, a honey-seller, has 9 litres of honey with her. If she sells 7500 ml of honey, how much honey is left with her?

  1. 15,000 ml

  2. 1,500 ml

  3. 15 ml

  4. 2,500 ml

  5. 150 ml


Correct Option: B
Explanation:

Amount of honey with Priya = 9 Litres = 9 * 1000 ml = 9,000 ml Amount of honey sold = 7,500 ml Therefore, the amount of honey left with Priya can be, 9,000 - 7,500 = 1,500 ml.  Thus, 1,500 ml of honey is left with Priya. The correct answer is option (2).

Which of the following expressions is obtained on multiplying 39 with the difference of 20 and 6?

  1. 39 - (20 x 6)

  2. (39 x 20) - 6

  3. 39 x (6 - 20 )

  4. 39 x (20 - 6)

  5. None of these


Correct Option: D
Explanation:

Since 20 > 6, the difference of 20 and 6 can be represented as (20 - 6). Accordingly, the multiplication of 39 with the difference of 20 and 6 can be represented as 39 x (20 - 6). Thus, the required expression is 39 x (20 - 6). The correct answer is option (4). 

Priya's current age is four more than three times the current age of her nephew Praveen, who is 12 years old. Which expression represents Priya's current age (in years)?

  1. 4 * (12 + 3)

  2. 4 + (3 * 12)

  3. 3 + (4 * 12)

  4. 3 * (12 + 4)

  5. None of these


Correct Option: B
Explanation:

Praveen's current age is 12 years.  Three times the current age of Praveen = (3 * 12) years  It is given that Priya's current age is four more than three times the current age of Praveen. Thus, Priya's current age (in years) is 4 + (3 * 12). The correct answer is option (2).

The multiplication of the Roman numerals LV and XCIII can be written in Hindu-Arabic numerals as

  1. 5115

  2. 5105

  3. 4115

  4. 3105

  5. 5125


Correct Option: A
Explanation:

The given Roman numerals are LV and XCIII. The first numeral can also be written as LV = L + V = 50 + 5      ..........[L = 50; V = 5]  = 55 The second numeral can also be written as XCIII = XC + III = (100 - 10) + 3      ................[X = 10; C = 100; III =3] = 93 Therefore, LV x XCIII = 55 * 93 = 5115 The correct answer is option (1).

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