can someone correct this for me parts A-E and if i am wrong can you help me....please
How many 7-digit telephone numbers are possible if the first digit cannot be zero and.....
a) only odd digits may be used?
my answer: 8125
b) the telephone number must be multiple of 10(that is , it must end in zero)?
my answer: 1,000,000
c) the telephone number must be a multiple of 100?
my answer 100,000
d) the first 3 digits are 481?
my answer 10,000
e) no repetitions are allowd?
my answer: 120
I will be happy to critique your work.