a)how many 5 digit numbers are there that exclude 0 and 7The digits that exclude 0 and 7 are {1,2,3,4,5,6,8,9}
Choose the first digit 8 ways.
Choose the second digit 8 ways.
Choose the third digit 8 ways.
Choose the fourth digit 8 ways
Choose the fifth digit 8 ways.
8×8×8×8×8 = 85 = 32768 ways.
b) How many of them start with an even numberChoose the first digit 4 ways.
Choose the second digit 8 ways.
Choose the third digit 8 ways.
Choose the fourth digit 8 ways
Choose the fifth digit 8 ways.
4×8×8×8×8 = 4×84 = 4×4096 = 16384 ways.
c) how many of them start and end with and even numberChoose the first digit 4 ways.
Choose the second digit 8 ways.
Choose the third digit 8 ways.
Choose the fourth digit 8 ways
Choose the fifth digit 4 ways.
4×8×8×8×4 = 4×83×4 = 4×512×4 = 8192 ways.
Edwin