One question that isn't hard but had method

 And is planing and attack, so you see the problem and at first glance appear dificult when I was in teh begining I used to explore all the possibilities and making a beautiful table of all that I could discover and stoped an interpretation of the informations I finishes the problem, but all very well described, just take sometime but I worked very fast, and write well was part to I don't got lost in so much information, but I passedto observation planing and attack the problem, that is for the arm for a desease like give the right medication, the medication the attack. So to the quesiton.

To get to a certain city, a driver noticed that his vehicle consumed 12 liters of fuel for every 100 km he drove. The 450 km journey took 6 hours. Under these conditions, how many liters of fuel were consumed per hour? 

A) 9 liters

B) 12 liters 

C) 54 liters

D) 72 liters

Organization of a matematical way what was write por extension, put things to the egineer of the mathematics:

12L    _______  100km - 12 liters of gas make 100km

450Km    _______  6H     -  all the trip was 450Km and took 6hours

So now observation and planning⏳Let's discover how much liters was spent in all trip:

450Km/100Km = x/12 -> So in all trip was spent 54liters of gas, is the grandity in common, the kilometers, so in the 1st equation I had that 100Km is 12 liters and I compare with the part of the other information that is the trip was 450kilometers I want discover is the time but I have the distance, so with the liters by the trip I gonna compare with the 6 hours to know how much was spent in one hour because I discover that in 450Km is 54liters, and I knowing that 450Km is all the trip I can compare directly 54liters with 6 hours, isn't that simple but is the way you need see how the calculation without the explanation is extremelly short so 

54L/y = 6h/1h -> y = 9 liters. Everyboy can work with complex comparisions isn't direct, is of secon grade, is you give one information that you to discover you have to compare not direct you need make a comparation with something in common.

Rute Bezerra de Menezes Gondim