The new N5 points かかる and する - finding the difference impossible to grasp with the given examples

[The111]

For reference:

https://bunpro.jp/grammar_points/する-cost

https://bunpro.jp/grammar_points/かかる-time-cost

I do sort of understand the difference as described in the lessons, but the examples do not all seem to fit perfectly, and they are incredibly strict about only accepting one possibility. E.g. consider these two, one from each lesson:

How are these different??? Both are describing a high price for a one day travel expense (a hotel vs a flight).

These are not the only two causing me problems. I’ve been stuck in beginner stage for these two points for many days now because the questions just seem like a crapshoot. No other N5 point has ever given me such a hard time.

And as a sidenote, a hotel that costs $44k USD per night? Really? What is up with these unbelievably high price sentences recently?

[JamesBunpro]

かかる generally focuses on how much money something takes (the “burden”) to do. する tends to focus on the actual price and is frequently used when emphasising expense.

As for the review questions being too strict, on some of the new grammar points we are yet to tidy up what answers should or shouldn’t be accepted as alternatives or bounced back. I’ll try make sure this one gets sorted as soon as possible, since this generally shouldn’t be an automatic fail. Sorry for the inconvenience on that one