Playing With Numbers

32. If a number divides three numbers exactly, it must be divisible by

  • (A) 9
  • (B) 6
  • (C) 3
  • (D) 12

31. The sum of the factors of 6 is

  • (A) 45
  • (B) 60
  • (C) 75
  • (D) 90

30. The number of factors of 36 is

  • (A) 6
  • (B) 7
  • (C) 8
  • (D) 9

29. What is the sum of all the factors of 36?

  • (A) 97
  • (B) 91         
  • (C) 90         
  • (D) 89

28. Number of factors of the number 68 is

  • (A) 8
  • (B) 18
  • (C) 28
  • (D) 48

27. Which among the following is an example of a perfect number?

  • (A) 8
  • (B) 18
  • (C) 28
  • (D) 48

26. The sum of first three common multiples of 3, 4 and 9 is

  • (A) 108
  • (B) 144
  • (C) 252
  • (D) 216

25. The number of distinct prime factors of the largest 4-digit number is

  • (A) 2
  • (B) 3
  • (C) 5
  • (D) 11

24. The number of distinct prime factors of the smallest 5-digit number is

  • (A) 2
  • (B) 4
  • (C) 6
  • (D) 8

23. If the number 7254*98 is divisible by 22, the digit at * is

  • (A) 1
  • (B) 2
  • (C) 6
  • (D) 0

22. The largest number which always divides the sum of any pair of consecutive odd numbers is

  • (A) 2
  • (B) 4
  • (C) 6
  • (D) 8

21. Which of the following number is divisible by 3?

  • (A) 121       
  • (B) 123       
  • (C) 124       
  • (D) 122

20. A number is divisible by 4 if its

  • (A) last digit is 4  
  • (B) last digit is 0
  • (C) last two digits are divisible by 4
  • (D) last digit is 8

19. A number is divisible by 5 and 6. It may not be divisible by

  • (A) 10
  • (B) 15
  • (C) 30
  • (D) 60

18. The sum of the prime factors of 1729 is

  • (A) 13
  • (B) 19
  • (C) 32
  • (D) 39

17. The greatest number which always divides the product of the predecessor and successor of an odd natural number other than 1, is

  • (A) 6
  • (B) 4
  • (C) 16
  • (D) 8

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