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In how many ways is it possible to arrange the digits of 1150 to get a four-digit multiple of 5?

 Aug 3, 2020
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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.

 Aug 3, 2020

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