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avatar+64 

What is the least positive multiple of 25 for which the product of its digits is also a positive multiple of 25?

 Sep 26, 2019
 #1
avatar+2417 
+3

Lets do it the dumb way

 

25 - the digit's product is 10, so no.

 

50 - 0 , so no.

 

75 - 35, so no.

 

100 - 0 so no.

 

125, 150, and 175 and 200 are no because of our past pattern

 

225 - 20, so no.

 

250 - 0 so no.

 

275 - 70 so no.

 

300 - so no.

 

325 - 30, so no.

 

 

Notice the bolded, every 25 the product of its digits increase by 10.

 

So,

 

325 - 30

 

425 - 40

 

525 - 50.

 

 

 

 

 

525 is answer

 Sep 26, 2019
 #2
avatar+104962 
+2

Good job, CU   !!!

 

 

 

cool cool cool

CPhill  Sep 26, 2019
 #3
avatar+64 
+1

thank you!

 Sep 26, 2019

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