SOLUTION: The digits 1,2,3,4 and 5 are to be used to form a five-digit number. How many different numbers can be formed if (1)repetitions are permitted? (2)repetition is not allowed? (3)the

Algebra ->  Probability-and-statistics -> SOLUTION: The digits 1,2,3,4 and 5 are to be used to form a five-digit number. How many different numbers can be formed if (1)repetitions are permitted? (2)repetition is not allowed? (3)the       Log On


   

Question 987637: The digits 1,2,3,4 and 5 are to be used to form a five-digit number. How many different numbers can be formed if (1)repetitions are permitted? (2)repetition is not allowed? (3)the number must be odd and repetitions are not allowed?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Imagine you have 5 boxes. There are 5 numbers
you can put in each of the boxes, so if repetitions
are allowed, the possible numbers total:
+5%2A5%2A5%2A5%2A5+=+3125+
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If repetitions are not allowed,
+5%2A4%2A3%2A2%2A1+=+1200+ numbers are possible
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Repetitions are not allowed
Now just get rid of all the numbers that end
with 2 or 4 and you are left with the odd numbers
+1200+-+%28+4%2A3%2A2%2A1%2A1+%2B+4%2A3%2A2%2A1%2A1+%29+
( the addition is for ending in 2 OR ending in 4 )
+1200+-+2%2A24+=+1200+-+48+
+1200+-+48+=+1152+ possible numbers
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Hope I got it!