The number of 5-digit integers formed by the digits 0,3,4,5,6,8 in the interval [3502, 5472] is
4855
3955
5455
6595
Given that,
The number of 5-digit integers formed by the digits 0,3,4,5,6,8 in the interval [3502, 5472].
Let us consider the 1st digit as A, the 2nd digit as B, the 3rd digit as C, the 4th digit as D, and the 5th digit as E.
Position A has the digits 3, 4, and 5.
If the digits 0, 6, and 8 are put in position A then it will not be in the range [3502, 5472].
So, position A can be filled with 3, 4, and 5 in ways.
Position B can be filled with any one of the digits 0, 3, 4, 5, 6, and 8 in ways.
Position C can be filled with any one of the digits 0, 3, 4, 5, 6, and 8 in ways
Position D can be filled with any one of the digits 0, 3, 4, 5, 6, and 8 in ways.
Position E can be filled with any one of the digits 0, 3, 4, 5, 6, and 8 in ways.
Thus, the number of ways of the number starting with 3, 4, and 5 is given by,
Now, we have to find the number which starts with 3 and 5 but doesn’t fall in the range [3502, 5472].
The possible way of starting the number with 300 is 6.
Placing 0 in the last place in 3502 will be less than the range.
So, the possible way is 1.
Considering the number 5472, here the 2nd place is filled with 5 or 6 will go beyond the range. In the 3rd place, any of the 6 digits can be placed.
So, the possible way is .
The total number which starts with 3 and 5 but doesn’t fall in the range is,
Therefore, the total number falls in the range is 3888+67 = 3955.
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