Consider the statement: If demand curves are always downward-sloping and we have 4,000 units sold when we charged $20 for our product, then increasing our price to $25 will result in sales less than 4,000.

In your discussion post, prove this statement using a direct proof. Also, prove this statement by transposition.

responses are to be fully detailed with examples. Be sure to identify the source of your example in your posting, remember citations and references.