number of ways by which 4digit no made where aless than b,bless than c,c less than d where all lies between 1 to 9
Choose the correct choice from the following.
A) 1290
B) 1296
C) 1380
D) 1480
E) 1580
we have to make 4 digit number   in which the format is d&gt; c &gt; b &gt; a   __ __ __ __   1st position can be filled by 6 digits(9, 8, 7, 6, 5, 4)   2nd position can be filled by 6 digits(8, 7, 6, 5, 4, 3)   3rd position can be filled by 6 digits(7, 6, 5, 4, 3, 2)   4th position can be filled by 6 digits(6, 5, 4, 3, 2, 1)   hence every place can be filled by 6 digits,   6* 6* 6* 6= 
<gadget id="calculator">6* 6* 6* 6</gadget>
<output>1_296</output>
1296   ANSWER:1296
<result>B</result>
number of ways by which 4digit no made where aless than b,bless than c,c less than d where all lies between 1 to 9