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Given the four digits 2, 4, 6, and 7, how many different positive two-digit integers can be formed using these digits if a digit can be repeated in an integer?

 Jun 13, 2020
 #1
avatar+1130 
+3
​there can be 5+4+3+2+1=15 ways to do it and
you can flip them 2 times to get 15*4=60

Answer=60

 Jun 13, 2020
edited by jimkey17  Jun 13, 2020
edited by jimkey17  Jun 13, 2020
 #5
avatar
-1

Since each digit can be repeated, the number of permutations is: 2^4 = 16

 

{2, 2} | {2, 4} | {2, 6} | {2, 7} | {4, 2} | {4, 4} | {4, 6} | {4, 7} | {6, 2} | {6, 4} | {6, 6} | {6, 7} | {7, 2} | {7, 4} | {7, 6} | {7, 7} (total: 16)

 Jun 13, 2020

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