Question bank/JEE Main/Mathematics
JEE MainMathematicsModeratePemutation and combination
Number of natural number's less than 7000 using digit 0, 1, 3,
7, 9 (repetition allowed) is
Show answer and solution
Ist 2st 3st 4st
position position position position
There are 3 way to fill I^st position (0, 1, 3) for remaining digits
there are 5 ways.
(0000 is not included)
hence required ans = 3.5.5.5 - 1 = 375- 1 = 374
position position position position
There are 3 way to fill I^st position (0, 1, 3) for remaining digits
there are 5 ways.
(0000 is not included)
hence required ans = 3.5.5.5 - 1 = 375- 1 = 374
Source: Grass-G / M-11 Mathematics Paper-2 1Nov.docx
Need a video for this idea?
Scan any doubt from your notes and get a whiteboard explanation.