well, right now it isn't near $90 but near $80..... (the minimum by law is 2050 pesos, and since a dollar = 24.75 pesos, it's actually around $82)
and the $40 on expenses per month is because, by law, the minimum wage must be double of the cost of the "canasta familiar" (all the basic things to make it through the month, so to speak

), but it excludes phone, electricity and water bills...
so, that's the reason one must do their best and get through college ^^