+65 The product of the digits of 3214 is 24. How many distinct four-digit positive integers are such that the product of their digits equals 12?
1134
1143
1223
1232
1314
1322
1341
1413
1431
2123
2132
2213
2231
2312
2321
3114
3122
3141
3212
3221
3411
4113
4131
4311
==> 24 numbers
If by "distinct four-digits" you mean "no repeats allowed", then the answer is =0 or none! if you allow repeats as as 1126, then you have a total = 36 such numbers.
1126 1134 1143 1162 1216 1223 1232 1261 1314 1322 1341 1413 1431 1612 1621 2116 2123 2132 2161 2213 2231 2312 2321 2611 3114 3122 3141 3212 3221 3411 4113 4131 4311 6112 6121 6211 Total = 36
