Math? Yuck. We managed to avoid those riddles up ’till now. I guess I have a good one, too, then. This was an actual SAT question that no one was able to answer, from back when the T stood for test (oy, I hate making myself look old).
If a person drives to a place at 40 MPH, and then drives back at 30 MPH, and the total trip takes 1 hour with no stops, what is the average speed for the trip? [Note that the distance is the same both ways, and the speed in each direction is not an average but an exact and constant speed].
I think that the 9’s is the only one left outstanding – but it is not specified what order of operation to use.