Determine whether the given argument is valid. For the valid argument, construct a formal proof. k. If it rains, then the outing is postponed. If the outing is postponed, then the budget is forfeited....

Determine whether the given argument is valid. For the valid argument, construct a formal proof.

Extracted text: k. If it rains, then the outing is postponed. If the outing is postponed, then the budget is forfeited. Therefore, if it rains, then the budget is forfeited.