Question: How many three-digit numbers are composed of three distinct digits such that one digit is the average of the other two?
How can this be solved with an arithmetic sequence?
I can see that any two digits must be same parity to produce the even sum. Also any two of the digits must be divisible by 2. if ¯abc is the digit, a+b=2c and doing that for all three digits gives three equations. Thats as far as I can get.
No comments:
Post a Comment