I agree. Its said commonly if one doesnt say "why do you want 50 pesos". Reporting it.
Always think of para qué as for what purpose. It is used a lot in Spanish, in cases where it would be improper to use por qué, which really means for what reason.
In English, we use why for both---so it's wise to take a step back and differentiate the two, before translating.
but, technically "why:" should be "porque", no? Para que literally mean "for what" and should be accepted as well as "why". These new sentences need some serious editing. Duo has no trouble with awkward (usuually literal) English when it suits it, but then it changes its mind and wants less literal translations at other times.
Por que also literally means "for what". And that phrase is a somewhat archaic way of asking "why" in English, too.
No, the point is that we're asking what you will do with the fifty pesos. What's it for, not why do you want it. Notice that it wasn't por que, it was para que.
I too have pointed this out elsewhere. It is very frustrating and inconsistent.
I really thought it was "What do you want for 50 pesos." Like a commentary on cheap products. As the sentences get longer, I struggle more with the different word order from English.
I put "what" as the first word and it said, "You used the wrong word."! I get so frustrated at that crap.
It's the best way to learn! I too hate it when it "dings" me, but I realize I won't get it wrong the next time~
Donald798622 as a result of that harsh ding you will Aways spell it correctly going forward !