Options:
A) 120
B) 300
C) 420
D) 20
  Show Answer
  Answer:
Correct Answer: C
Solution:
- The units place can be filled in 4 ways as any one of 0, 2, 4 or 6 can be placed there. The remaining three places can be filled in with remaining 6 digits in  $ ^{6}P_3 $  = 120 way. So, total number of ways = 4 × 120 = 480. But, this includes those numbers in which 0 is fixed in extreme left place. Numbers of such numbers  $ =3\times {{}^{5}}P_2=3\times 5\times 4=60 $
0 × × ×
Fix  $ ^{5}P_2 $  ways 3 ways  (only 2, 4 or 6)
\ Required number of ways = 480 - 60 = 420.