Question

Number of four different digits are formed from the digits $1,2,3,4,5,6,7,8,9$. How many of them are greater than $4000$?

• A. $2010$
• B. ${{}^{9}P}_4$
• C. $2016$
• D. none of these

Answer 1

Answer: (C)

$2016$

$\underset{–}{x}\underset{–}{y}\underset{–}{z}\underset{–}{w}$

$x\ge 4,y,z,w\ge 0$

number of ways = ${}^{6}G{\times }^9-1C_3\times \lfloor 3$

$6\times \lfloor 8-\lfloor 3$

$\lfloor 3\lfloor 5$

$=6\times 6\times 7\times 8$

$=2016$

$\therefore D$