Magical Mathematics[Interesting Approach]
how many four digit numbers can be formed such that the digits are in the decreasing order
how many four digit numbers can be formed such that the digits are in the decreasing order
1 Answer
Shobhit Varshney
Dear student,
Number of such numbers without having zero in the number = (9*8*7*6) / 4! = 126
Number of such numbers with having zero in the number = (9*8*7) / 3! = 84
Therefore, number of such numbers = (126+84) = 210
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Number of such numbers without having zero in the number = (9*8*7*6) / 4! = 126
Number of such numbers with having zero in the number = (9*8*7) / 3! = 84
Therefore, number of such numbers = (126+84) = 210
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