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# A seven digit number is in form of abcdefg (g, f, e, etc. are digits at units, tens, hundred place etc.) where a < b < c < d > e > f > g. The number of such numbers are

- 1981
- 2009
- 1560
- 1870

## The correct answer is: 1560

### Cases : i) If d = 6 then seven digit numbers possible are = ^{5}C_{3}. ^{3}C_{3}

[as a,b,c can be choosen from 1,2,3,4 or 5 & similarly e,f,g can be choosen from the unused 2 digit which are less than 6 & 0 can be used]

ii) If d = 7 then numbers possible =,

iii) If d = 8 then numbers possible =

iv) If d = 9 then numbers possible =

Add all cases

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