how would you do this question: How many 7 digit even numbers less than 3000000 can be formed using all the digits 1,2,2,3,5,5,6 ? I have tried using permutations and subsets but it doesnt seem to work.
+118654 how would you do this question: How many 7 digit even numbers less than 3000000 can be formed using all the digits 1,2,2,3,5,5,6 ? I have tried using permutations and subsets but it doesnt seem to work.
It must start in 1 or 2 and it must end in 2 or 6
1 - - - - - 2 5! /2! ways
1 - - - - - 6 5! / 2!2! ways
2 - - - - - 2 5! / 2! ways
2 - - - - - 6 5! / 2! ways
Total
5!/2 + 5!/4 + 5!/2 + 5!/2 = 1.75*5! = 210
Does that agree with your answer? If not, what is your answer?
