Question

Fan and Medal! Proofing!

Answer 1

Alex wrote the following indirect proof:

Prove: 13 is a factor of 195

Step 1: Assume that 13 is not a factor of 195.
Step 2: 195 divided by 13 is 15.
Step 3: A factor is an integer by which another integer is a multiple.
Step 4: Therefore, 13 must be a factor of 195.

Which step in Alex's proof is incorrect?

Answer 2

Step 1

Step 2

Step 3

Step 4

Answer 3

I think its 3

Answer 4

this is weird

Answer 5

So its step 4?

Answer 6

I guess 3

A factor is a integer by which another integer is a multiple

take 16

3 is not a factor of 16 but 3 = 3*1