stadel proportion

 

Presented without comment, and with thanks to Andrew.

  • Apparently it is – and it’s much easier than the insanity-producing cross-multiplication. Of course, it’s not a procedure that would give one any answers that meet with any other reality, but it’s still easier. 🙂

  • I would want to teach this kid to multiply both sides by 30 as the first step in a problem like this — same as solving any other type of equation in which the variable only occurs once, use inverse operations to isolate your variable.