"Assuming mistakes will lead to positive results is not a valid answer for any problem."

An equally valid answer is that in recent years state educators have run after every kind of faddish educational practice.

Is "'cause it felt like it" a valid answer at this point?

This is a machine to be constructed to give us valid answers.

He abruptly realized that the problem had an unlimited number of equally valid answers.

This answer, if valid, certainly smashed the first horn of the dilemma, and for a while excited him greatly.

We're not really prepared for a culture where a million (or a billion) people are valid answers in 20 Questions.

The buyer posts a request, normally in the form of a question and sets a price for the valid answer.

Five rounds make up a complete game, with scoring based on the number of valid answers given.

There is really no valid answer but your own.