Question 985039: If you consider the numbers 1,2,3,4, and 5, how many three digit numbers can be formed if:
A. Repetition is not allowed and such that they are all:
1. Greater than 200
2. Ending in 5
3. odd numbers
B. Repetition is allowed such that they are all:
1. even numbers
2. Less than 500
3. having 1 or 5 in their hundreds place
Answer by macston(5194)   (Show Source):
You can put this solution on YOUR website! .
A. Repetition is not allowed and such that they are all:
1. Greater than 200
The hundreds unit must be greater than 1, so there are 4 choices, 4 remaining choices for tens, and 3 choices for units:
4 x 4 x 3 = 48 possible numbers
.
2. Ending in 5
One choice for units, 4 remaining for tens, 3 for hundreds:
1 x 4 x 3 = 12 possible numbers
.
3. odd numbers
Three choices for units, 4 remaining for tens, 3 for hundreds:
3 x 4 x 3 = 36 possible numbers
.
B. Repetition is allowed such that they are all:
1. even numbers
Two choices for units, 5 for tens and 5 for hundreds:
2 x 5 x 5 = 50 possible numbers
.
2. Less than 500
Three choices for hundreds, 5 for tens, 5 for units:
3 x 5 x 5 =75 possible numbers
.
3. having 1 or 5 in their hundreds place
2 choices for hundreds, 5 for tens, five for units:
2 x 5 x 5 = 50 possible numbers
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