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How many four digit even numbers can be formed from the set {0,1,2,3,4,5,6,7} if repetition of digits is not allowed?
A. 1470
B. 750
C. 720
D. 540
Is it right I got 720 from 6*5*6*4?
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Any of 7 digits in the first (very left) position (all except 0);
Any of 4 even digits in the fourth, very last position;
Any of remaining 8-2 = 6 digits in the second position from the left;
Any of remaining 5 digits in the third position from the left.
7*4*6*5 = 840 numbers.