Permutation and CombinationHard
Question
Using all digits 2,3,4,5,6, how many even numbers can be formed?
Options
A.24
B.48
C.72
D.120
Solution
number ending with 2,4,6 can only form even number.
FIRST FOUR PLACES CAN BE FILLED IN 4! WAYS
LAST DIGIT FILLED IN 3 MANNER
SO TOTAL NUMBER = 4! × 3 = 72
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