Reb “I can only try”,
I saw this somewhere before (possibly when I took the SATs…).
Here’s how I did it-
40 MPH = (2/3) MPM (Miles Per Minute)
30 MPH = (1/2) MPM
=> x*(2/3) = (60-x)*(1/2) => x = 180/7 = 25.71429 and (60-x) = 34.28571.
The weighted average is (25.71429/60)*40 + (34.28571/60)*30 = 34.28571, which was choice A.
How did you know I was a teacher? Were you a student of mine? I was actually a teacher while I was going for my Ph.D (hence the Dr. title) but no longer teach.
If you like these math riddles let me know, I’ve got some more of them which might be too technical for most people reading this thread.
Also I was just kidding about the answer being A, I don’t remember the choices.