Algebra 2
posted by Anonymous .
Using the integers 2,3,4,5,
How many 3digit odd numbers less than 300 can be formed if no repetition of digits is allowed?
Please explain and show work.

Since it's an odd number LESS than 300 we know that the first number can only be 2 and therefore we have only 1 choice for the first unit. Since it's an ODD number we know that the last unit is either 3 or 5 (2 choices). No we are left with either 4 and 3 or 5 (depending on which one was chosen for the last unit), therefore we have 2 choices for the middle unit. Hence, the answer is 1x2x2 = 4 numbers.
Just for assurance, let's list out the numbers
235
245
253
243