'solid question' is a correct and usable phrase in written English. You can use it to express that a certain question is a valid, meaningful, and relevant one. For example, "The reporter asked a solid question about the mayor's plans for the future of the city.".
It's a solid question, and one we might not be able to answer for some time.
Lashinsky does ask one solid question at the end – Would you invest your new venture fund in Ning at a $750 million valuation, he asks?
You will not be interrupted from reading a solid question.
A solid question that I put to the governor in one of our meetings, Mr. Governor, would you go back to your people and ask them if they would estimate when do they think we will not be able to make a school aid payment.
Still, he saw himself as a real senator -- a sort of state-level version of Ted Kennedy or Richard Shelby -- a guy who asks good, solid questions at hearings.
Obviously, you have to be sure the data you have is based on solid questions that produced accurate information and follows best data gathering practices –but even then it's possible to produce unexpected outcomes, proving just following the data isn't always as simple as it sounds.
Although air quality was dramatically improved, and Pittsburgh's manufacturing base seemed solid, questions abound about the negative effects Urban Renewal continues to have on the social fabric of Pittsburgh.
Ludwig does not simply clarify my doubts with English writing, it enlightens my writing with new possibilities
Simone Ivan Conte
Software Engineer at Adobe, UK