Question 684488: how many three-digit numbers greater than 600 can be performed by using the digits 4,5,6,7,8
Answer by Edwin McCravy(20054) (Show Source):
You can put this solution on YOUR website! how many three-digit numbers greater than 600 can be performed by using the digits 4,5,6,7,8
We can choose the first digit any of these 3 ways: {6,7,8}
For each of those 3 ways we can choose the first digit,
we can then choose the second digit any of these 5 ways {4,5,6,7,8}
That's 3×5 or 15 ways to chose the first and second digits.
For each of those 15 ways we can choose the first and second digits,
we can then choose the third digit any of these 5 ways {4,5,6,7,8}
That's 15×5 or 75 ways to chose the first, second, and third digits,
so that's the answer.
Answer: 75
Here are all 75 three digit numbers:
1. 644 2. 645 3. 646 4. 647 5. 648 6. 654 7. 655 8. 656 9. 657 10. 658
11. 664 12. 665 13. 666 14. 667 15. 668 16. 674 17. 675 18. 676 19. 677 20. 678
21. 684 22. 685 23. 686 24. 687 25. 688 26. 744 27. 745 28. 746 29. 747 30. 748
31. 754 32. 755 33. 756 34. 757 35. 758 36. 764 37. 765 38. 766 39. 767 40. 768
41. 774 42. 775 43. 776 44. 777 45. 778 46. 784 47. 785 48. 786 49. 787 50. 788
51. 844 52. 845 53. 846 54. 847 55. 848 56. 854 57. 855 58. 856 59. 857 60. 858
61. 864 62. 865 63. 866 64. 867 65. 868 66. 874 67. 875 68. 876 69. 877 70. 878
71. 884 72. 885 73. 886 74. 887 75. 888
Edwin
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