Real Numbers - LCM and HCF

LCM and HCF of Real Numbers

15 Questions Published

Questions

Question 1 Multiple Choice (Single Answer)

If A = 2n + 13 and B = n + 7, where n is a natural number, then HCF of A and B is

  1. 2
  2. 3
  3. 1
  4. 4
  5. 5
Question 2 Multiple Choice (Single Answer)

The LCM of 5, 8, 12 and 20 will not be a multiple of

  1. 5
  2. 3
  3. 9
  4. 20
  5. 8
Question 3 Multiple Choice (Single Answer)

Three runners running around a circular track can complete one revolution in 2, 3 and 4 hrs, respectively. They will meet again at the starting point after

  1. 8 hrs
  2. 6 hrs
  3. 12 hrs
  4. 18 hrs
  5. 24 hrs
Question 4 Multiple Choice (Single Answer)

The pairs of natural numbers having least common multiple 78 and greatest common divisor 13 are

  1. 58 and 13 or 16 and 39
  2. 68 and 23 or 36 and 49
  3. 18 and 73 or 56 and 93
  4. 78 and 13 or 26 and 39
  5. 88 and 13 or 26 and 39
Question 5 Multiple Choice (Single Answer)

Two natural numbers have their sum as 85 and LCM as 102. Which of the following are the two numbers?

  1. 30 and 55
  2. 17 and 68
  3. 35 and 55
  4. 51 and 34
  5. 55 and 30
Question 6 Multiple Choice (Single Answer)

Four bells toll together at 9.00 am. They toll after 7, 8, 11 and 12 seconds, respectively. How many times will they toll together again in the next 3 hours?

  1. 3
  2. 4
  3. 5
  4. 9
  5. 7
Question 7 Multiple Choice (Single Answer)

Two natural numbers with difference 66 and LCM 360 are

  1. 120 and 54
  2. 90 and 24
  3. 180 and 114
  4. 130 and 64
  5. 136 and 70
Question 8 Multiple Choice (Single Answer)

The LCM of 2.5, 0.5 and 0.175 is

  1. 2.5
  2. 5
  3. 7.5
  4. 17.5
  5. 1.75
Question 9 Multiple Choice (Single Answer)

What is the smallest number which when increased by 6 becomes divisible by 36, 63 and 108?

  1. 750
  2. 752
  3. 754
  4. 756
  5. 758
Question 10 Multiple Choice (Single Answer)

The HCF and LCM of two numbers are 33 and 264, respectively. When the first number is completely divided by 2, the quotient is 33. The other number is

  1. 66
  2. 130
  3. 132
  4. 196
  5. 135
Question 11 Multiple Choice (Single Answer)

Two alarm clocks beep at regular intervals of 50 seconds and 48 seconds. If they first beep together at 12.00 pm noon, at what time will they beep again?

  1. 12:20 pm
  2. 12:12 pm
  3. 12:11 pm
  4. 12:15 pm
  5. None of these
Question 12 Multiple Choice (Single Answer)

Two friends were discussing their marks in an examination. While doing so, they realised that both the numbers had the same prime factors, although one got a score which had two more factors than the other. If their marks are represented by one of the option as given below, which option is correct?

  1. 30, 60
  2. 20, 80
  3. 40, 80
  4. 20, 60
  5. 10, 20
Question 13 Multiple Choice (Single Answer)

Two equilateral triangles have sides of lengths 34 cm and 85 cm. The greatest length of tape that can measure the sides of both of them exactly is

  1. 34 cm
  2. 17 cm
  3. 51 cm
  4. 68 cm
  5. None of these
Question 14 Multiple Choice (Single Answer)

The HCF of 2472, 1284 and a third number N is 12. If their LCM is 23 x 32 x 5 x 103 x 107, then the number N is

  1. 22 x 32 x 7
  2. 22 x 33 x 103
  3. 22 x 32 x 5
  4. 24 x 32 x 11
  5. 21 x 33 x 15
Question 15 Multiple Choice (Single Answer)

There are three pieces of timber of lengths 42 m, 49 m and 63 m. These have to be divided into planks of the same length. The least possible number of planks is

  1. 5
  2. 11
  3. 13
  4. 8
  5. None of these