AABBCD
We first work it as if the A's were distinguishable, as if it were
AaBbCD
Then there would be 6! = 720 ways
However, the A and a could be arranged in each arrangement
in 2! ways, and the B and the b could be arranged in 2! ways,
and we wouldn't be able to tell the difference, so we must
divide twice by 2!.
Answer = = = 180 ways.
Here are all 180 ways:
1. AABBCD 2. AABBDC 3. AABCBD 4. AABCDB 5. AABDBC 6. AABDCB 7. AACBBD 8. AACBDB 9. AACDBB 10. AADBBC
11. AADBCB 12. AADCBB 13. ABABCD 14. ABABDC 15. ABACBD 16. ABACDB 17. ABADBC 18. ABADCB 19. ABBACD 20. ABBADC
21. ABBCAD 22. ABBCDA 23. ABBDAC 24. ABBDCA 25. ABCABD 26. ABCADB 27. ABCBAD 28. ABCBDA 29. ABCDAB 30. ABCDBA
31. ABDABC 32. ABDACB 33. ABDBAC 34. ABDBCA 35. ABDCAB 36. ABDCBA 37. ACABBD 38. ACABDB 39. ACADBB 40. ACBABD
41. ACBADB 42. ACBBAD 43. ACBBDA 44. ACBDAB 45. ACBDBA 46. ACDABB 47. ACDBAB 48. ACDBBA 49. ADABBC 50. ADABCB
51. ADACBB 52. ADBABC 53. ADBACB 54. ADBBAC 55. ADBBCA 56. ADBCAB 57. ADBCBA 58. ADCABB 59. ADCBAB 60. ADCBBA
61. BAABCD 62. BAABDC 63. BAACBD 64. BAACDB 65. BAADBC 66. BAADCB 67. BABACD 68. BABADC 69. BABCAD 70. BABCDA
71. BABDAC 72. BABDCA 73. BACABD 74. BACADB 75. BACBAD 76. BACBDA 77. BACDAB 78. BACDBA 79. BADABC 80. BADACB
81. BADBAC 82. BADBCA 83. BADCAB 84. BADCBA 85. BBAACD 86. BBAADC 87. BBACAD 88. BBACDA 89. BBADAC 90. BBADCA
91. BBCAAD 92. BBCADA 93. BBCDAA 94. BBDAAC 95. BBDACA 96. BBDCAA 97. BCAABD 98. BCAADB 99. BCABAD 100. BCABDA
101. BCADAB 102. BCADBA 103. BCBAAD 104. BCBADA 105. BCBDAA 106. BCDAAB 107. BCDABA 108. BCDBAA 109. BDAABC 110. BDAACB
111. BDABAC 112. BDABCA 113. BDACAB 114. BDACBA 115. BDBAAC 116. BDBACA 117. BDBCAA 118. BDCAAB 119. BDCABA 120. BDCBAA
121. CAABBD 122. CAABDB 123. CAADBB 124. CABABD 125. CABADB 126. CABBAD 127. CABBDA 128. CABDAB 129. CABDBA 130. CADABB
131. CADBAB 132. CADBBA 133. CBAABD 134. CBAADB 135. CBABAD 136. CBABDA 137. CBADAB 138. CBADBA 139. CBBAAD 140. CBBADA
141. CBBDAA 142. CBDAAB 143. CBDABA 144. CBDBAA 145. CDAABB 146. CDABAB 147. CDABBA 148. CDBAAB 149. CDBABA 150. CDBBAA
151. DAABBC 152. DAABCB 153. DAACBB 154. DABABC 155. DABACB 156. DABBAC 157. DABBCA 158. DABCAB 159. DABCBA 160. DACABB
161. DACBAB 162. DACBBA 163. DBAABC 164. DBAACB 165. DBABAC 166. DBABCA 167. DBACAB 168. DBACBA 169. DBBAAC 170. DBBACA
171. DBBCAA 172. DBCAAB 173. DBCABA 174. DBCBAA 175. DCAABB 176. DCABAB 177. DCABBA 178. DCBAAB 179. DCBABA 180. DCBBAA
Edwin