How many four-digit odd numbers do not use any digit more than once? Options.
A) 1728  B) 2160  C) 2240  D) 2268  E) 2520
Let a 4-digit number be represented by ABCD   Here A can have any value between 1 to 9 - so total 9   B can have any value between 0 to 9, but not A - so total 9   C can have any value between 0 to 9, but not A or B - so total 8   D can have any value between 0 to 9, but not A, B or C - so total 7   No. of ALL possible 4-digit nos (without repeating any digit) = 9*9*8*7= 
<gadget id="calculator">9*9*8*7</gadget>
<output>4_536</output>
4536   Half of these would be odd.   Therefor, no. of O22682268 possible 4-digit nos (without repeating any digit)= 4536 / 2= 
<gadget id="calculator">4536 / 2</gadget>
<output>2_268</output>
2268   Answer should be 2268.
<result>D</result>
How many four-digit odd numbers do not use any digit more than once?