Question

Angie did the following proof in her logic class. Which step in the indirect proof did she do incorrectly?

Prove: 12 is divisible by 6.

Step 1: Assume that 12 is not divisible by 6.

Step 2: 2 times 6 is equal to 12. 12 divided by 6 is 2.

Step 3: 12 is not divisible by 6. (4 points)


Step 3

Step 2

Step 1

Steps 1 and 2

Answer 1

@Secret-Ninja

Answer 2

@ganeshie8

Answer 3

well since 12/6 is 2
then what conclusion can you draw from that?

Answer 4

we say a number m is divisible by another number n (n is not zero)
if m/n=integer.

Answer 5

and m and n are integers of course

Answer 6

Step 3 is wrong right, because she just proved that 12 \(\small\cal\color{black}{was}\) divisible by 6.

Answer 7

Right?

Answer 8

twelve is divisible by 6

Answer 9

ok...........

Answer 10

ok.......

Answer 11

12 can either be divisible by 6, or not divisible by 6; it has to be exactly one of these 2 possibilities. Angie goes about proving divisibility by showing that the case where 12 isn't divisible by 6 has to be false. This is shown in steps 1&2. The conclusion of step 3 does not follow from steps 1&2