In how many ways is it possible to arrange the digits of 1150 to get a four-digit multiple of 5?
+1084 For a number to be divisible by 5, it has to end in a 0 or 5. Also, a 4 digit number can't start with 0.
We could do casework. Case 1, where it ends in 0, Case 2, where it ends in 5.
Case 1:
3*2*1*1
That gives us 6. Divide by 2!, and we get 3.
Case 2:
2*2*1*1
Divide by 2!, and we get 2.
2+3 is 5. Therefore, there are 5 ways to arrange the numbers.
