16. Consider the set of digits {1,3, 4,5,7,8,9}
a)If the digits cannot be repeated and if the middle digit must be an odd digit, how many three-digit numbers can be formed?
b)If the digits can be repeated, how many positive numbers less than 1000 can be formed?
17. Each telephone number in a city consists of 7 digits, the first of which must be 3 or 4. a) How many telephone numbers are possible?
b) How many telephone numbers start with 4 and contain the digit 5 at least once?
c) How many telephone numbers have no repeated digits?
18.In a dance class, the instructor taught 15 different movements. For a class presentation, the student has to perform 4 or 5 movements in sequence. What is the number of different presentation if
a) there is no restrictions?
b)the first and last movements must be the same?
Comments
Leave a comment