There is a similar structure on the money spent to learn. For example, food expenses, housing costs to live and school expenses to learn of many junior high school students are paid by their parents. So they can concentrate on just learning without worrying about expenses (*3).
On the other hand, workers have to earn and pay those cost by themselves.
First of all, we need to spend the time to earn expenses for living. After that, we can pay the cost of learning. If a textbook cost 3,000 yen and the food expenses for one month is 30,000 yen, one book corresponds to food expenses for three days. (*4)
- *3: Of course, some students have to earn tuition by themselves due to the circumstances of their families.
- *4: I did not translate yen (Japanese Yen, JPY) to other currency because I do not know your currency. Today 3,000 JPY is about 28 US Doller, 24 Euro, and 188 Chinese Yuan. The example of book and food costs are common one in Japan.