SOLUTION: 28. How many 4-digit numbers can be formed from set A= {0,1,2,3,4,5,6} if there is no repetition ( note: 0123 is not a 4-digit number because it equals 123.) d) How many of

Algebra ->  Exponents -> SOLUTION: 28. How many 4-digit numbers can be formed from set A= {0,1,2,3,4,5,6} if there is no repetition ( note: 0123 is not a 4-digit number because it equals 123.) d) How many of      Log On


   

Question 144802: 28. How many 4-digit numbers can be formed from set A= {0,1,2,3,4,5,6}
if there is no repetition ( note: 0123 is not a 4-digit number
because it equals 123.)
d) How many of the numbers are divisible by 5? (Hint: you must consider
2 cases)
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
There are only 6 choices for the 1st number, since I can't use 0
Once I choose that number, there are6 choices for the 2nd number, since
I can use 0. There are 5 choices for the 3rd and 4 choices
for the 4th number
The possible numbers are
6%2A6%2A5%2A4+=+720 answer
Any number in theis group of 720 that ends in 0 or 5 will be
divisible by 5
There are
6%2A6%2A5%2A1+=+180 of these that end in 0
6%2A6%2A5%2A1+=+180 of these that end in 5
So, the answer is 2%2A180+=+360 of the 4-digit number are
divisible by 5