Posted by ken on .
how many 7 digit numbers can be formed with the numbers 1, 2, 4, 7. (they are in brackets). the question wants two parts. (a) if the numbers can be repeared and (b) if repetation is not allowed

math 
drwls,
Any of 4 numbers can be selected 7 times in a row. The answer is 4^7 = 16,384