Browse · MATH
Printjmc
number theory senior
Problem
How many ways are there to fill in the tens digit and hundreds digit of so that it is divisible by ?
Solution
For integer to be divisible by , then must be divisible by . The only possibilities for are , , and . Possibility 1: . This gives us two possible values: , and . Possibility 2: . This gives us possible values, where is any integer from to , and . Possibility 3: . This is impossible since the digit cannot be greater than , Thus there are a total of possible values.
Final answer
9