A number is selected at random from to . What is the probability that the number is divisible by and has exactly two even digits?
- A
- B
- C
- D
Solution & Step-by-step Explanation
Total numbers from to = .
Let the three-digit number be represented as , where the first digit (hundreds place) is always (which is an odd digit).
For the number to have exactly two even digits, both (tens place) and (units place) MUST be even digits, because the hundreds digit is odd.
Even digits available: (total even digits).
Also, the number must be divisible by 2, which means the units digit must be even. Since is already required to be even to fulfill the digit condition, any selection where both and are even will automatically be divisible by .
Let's calculate the number of favorable combinations for digits and :
* Number of choices for (even) = (can be )
* Number of choices for (even) = (can be )
Total favorable outcomes = .
The required probability is:
Let the three-digit number be represented as , where the first digit (hundreds place) is always (which is an odd digit).
For the number to have exactly two even digits, both (tens place) and (units place) MUST be even digits, because the hundreds digit is odd.
Even digits available: (total even digits).
Also, the number must be divisible by 2, which means the units digit must be even. Since is already required to be even to fulfill the digit condition, any selection where both and are even will automatically be divisible by .
Let's calculate the number of favorable combinations for digits and :
* Number of choices for (even) = (can be )
* Number of choices for (even) = (can be )
Total favorable outcomes = .
The required probability is: