Question on "Proof by contradiction" I am a little confused whether the following set of arguments can constitute a proof by contradiction:
Required to prove: Statement A is true.
Assumption: Suppose statement A is false.
We then show that if A is false then a (different) statement B is true.
But, statement B is true implies A is true.
Hence, A must be true.
These set of arguments feel a bit bizzare to me and perhaps might be incorrect. I am unable find a mistake.

This technique is actually quite common.  The answer above from LuckyS is a nice one.  Here's my favorite simple example.

*

*We have three beans, each one either white or black.

*We will prove that there must a pair of beans of the same color.

*Suppose this is not so.

*Then the first two beans are not a pair of the same color, so one is white and the other is black.

*Then if the third bean is white, there is a pair of white beans, and if the third bean is black, there is a pair of black beans.

