REGRA DE TRÊS SIMPLES \Prof. Gis/ Matemática

Hey guys! Do you already know rule of three simple? If you don't know, I invite you to attend this class and I will explain this content that is very used in our daily lives.

Let's go? So welcome to my channel, I'm Gis and in this class you'll learn how to solve questions involving the simple rule of three. Do you already know why it's called the rule of three simple?

First, it's called the rule of three because we always have three known values ​​in the question and we try to find out who the fourth value is, so for that reason it's called the rule of three, okay, then it's called simple because in the rule of three simple I work with two magnitudes ok, we will also have classes on the rule of 3 composed which are of three or more magnitudes, ok, but before starting the class I will make those two requests for you: subscribe to the channel da Gis if you are not subscribed and leave a thumbs up for me ok! So let's start solving the question, what is the first guideline I give to the student when solving this type of question: first read the statement up to the first point, okay, and then remove the magnitudes involved in the statement. So let's read: five identical faucets fill a tank in 6 hours, so what are the two magnitudes involved there?

The number of taps, let's write here, look, the number of taps, and what is the other quantity? Will the tank be great? A tank, but to find out if this tank is going to be a greatness I'll read the rest.

How long would it take for three of these faucets to fill the same tank? Did we have variation in the number of tanks? No, go on, it's the same tank that's there, so that's why it's not that one, it's not considered great, okay?

So one quantity is the number of taps and the other quantity is time. Gis but why can't I write the time that is greatness? Did you attend the class in which I explained about magnitudes?

I explained the difference between magnitudes, measurement units and measurement instruments, just remembering that magnitude is everything that can be measured I don't measure faucets I measure the number of faucets I don't even deserve it I count the number of faucets I don't, I count on the faucets have and the time, the time is another, the other is the magnitude and the time in the case that is there is the unit of measurement ok! Now before putting the values ​​here, let's identify how these magnitudes are related if they are considered directly or inversely proportional and once again I'll leave the indication here for you so that you can watch, go back to the classes where I explained direct magnitudes and inversely proportional quantities ok! So let's go, the more taps I have if I increase the number of taps okay what will happen with the time to fill that same tank okay, the time will decrease because there are more taps filling the tank of course the time decreases when one little arrow only the other little arrow goes down they are considered inversely proportional magnitudes I'm just abbreviating here so we don't write her whole name ok, and now guys?

Now we are going to remove the values ​​because so far I have not written any values ​​I like to write the magnitudes and compare who they are and how they are related, then I put the numbers, so come on, I have then five faucets fill a tank in 6 hours is. How long then? Put a question mark you can put x for x ok I'm going to put a question mark because then it's general for everyone so everyone can learn ok, three of these faucets would fill the same tank.

And now how do I solve it? Everyone says, because I've already heard it, the rule is just to cross-multiply! Be careful, it's not all the rules that are cross-multiplied, this one is inversely proportional, so you can't cross-multiply, how are you going to have to multiply?

You'll have to multiply it, think about it with me, to remember, let's do a little trick for you to remember, think of a jeep when I say the word jeep without even having the same letters there I remember the jeep the one that goes on the road then there's a chip that walks in the mud, everything goes around doing the maneuvers there and then they created the jeep to go on the road, then the jeep that goes on the road it goes that way? He walks straight on the road right people? Just a little joke, I'm not going to take anything serious just so you can remember later how to do the rule of three when it's inversely proportional, okay?

And now, the jeep goes straight, so when I have exercises like that the magnitudes are inversely proportional, I'm not going to cross-multiply like everyone says, I'm going to multiply straight, remember the jeep, okay? I remember the cart let's draw the cart here? Gis is good at drawing, look at the jeep, remember the jeep going straight down the road, okay?

So I'm going to multiply straight, but what am I going to multiply straight? Is there any way I can multiply here, people? Let's multiply three by an unknown value there's no way to multiply I'm going to multiply those values ​​that have values, so let's multiply here the 5 with 6 .

How much is 5 x 6 people? 5 x 6 gives 30 and then after I multiplied then straight what there are values ​​I divide it by what's left. Who's left?

Who is alone there is the 3 so then I divide by three. 30 / 3 three equals 10, so in this case the question was how long would it take for three taps to fill the same tank? So the answer would be 10 hours, so that means that the value I was looking for here would be 10.

Does that make sense? Let's validate our answer to see if it makes sense. Five taps take 6 hours to fill the tank, if I reduce the number of taps to 3 what will happen over time?

He's going to have to increase, isn't he? Because they are inversely proportional, then the time increased, so it made sense that I did it, why did I say that ? and then it arrives at a value smaller than this one, it will not make sense, okay, there is always a value greater than the magnitudes here are inversely proportional, in this case, it has to have a greater value, okay?

Let's do more examples! Come on people! Look at the second question I brought up then, let's make a point then, the Gis car, pretend, travels an average of 12 km with one liter of fuel right?

Did you stop reading there, why did you stop there because you can already identify in that first part what are the magnitudes involved in the question? Have you managed to identify? So what are the car travels on average 12 km so 12 km is the distance isn't it?

So one quantity here is the distance that is given in kilometers than the unit of measurement with 1 liter of fuel and the other quantity is the amount of fuel so it will be the amount of fuel that is in liters okay, just to make it perfect here for you to understand, and now what is that other classic that I explained to you, I'll put the value now? Not before placing the values ​​will we identify whether those magnitudes are directly or inversely proportional. Let's make a diagram of that little arrow, the greater the distance I'm going to travel what will happen to the amount of fuel the more I drive with my car the more fuel is spent so the two little arrows are in the same direction if you wanted to ask the opposite how much the shorter my distance, the smaller the amount of fuel I spend.

They are also in the same direction, so it doesn't matter if I'm going up or down, as long as the two are in the same direction, okay, so as the two little arrows are in the same direction, we have what here are directly proportional magnitudes, look I will also abbreviate the same as I did with the jeep I will abbreviate the magnitudes directly proportional to GDP but I do the exercise more, right and now will it be that here it will also be like the jeep that goes straight that I will multiply straight here not here finally na directly proportional magnitude is the one that I do the same as everyone says that cross-multiply right only there in the inverse magnitude that I do today because I multiply straight so now I 'm going to put the values, so my distance is 12 km with 1 liter of fuel and how many liters of fuel this car, which is Gis's car, will cover 336 km. So 336 km he will spend how many liters of fuel? Again I put a question mark why I'm not doing it with the x because I'm not going to do that equation which is the standard way of solving it in the traditional way .

So I'm not going to multiply the jeep, I'm not going to do the jeep I'm not going to do the straight, when the GDP I do the cross multiplication, but who am I going to cross? Let's always work here with the values ​​that I have, can you multiply 12 with this one? I can't because here is the unknown value so who can I multiply?

I can multiply the 336 by one. 336 for one is 336 and then what do I do people? I take 336 which is the value given by the multiplication and what I do with the term that was left over which was 12 I divide it by 12.

So 336 divided by 12 I'm going to do the practical process here okay, it's a short process actually 2 times 12 is 24. 24 to 33 is left with 9 under six. That's eight times.

So it means that to travel the 336 km the distance I wanted and take a vacation, right, so pretend here to travel these 336 km I would spend 28 liters of fuel. Okay guys? So you saw the difference between when it's a jeep and when it's a jeep I multiply the two magnitudes that have a straight value and when it's a GDP I'm going to do a crossword like that, okay.

Then, if you get the hang of doing these two, you 'll be able to solve all the exercises you have there and you'll crush it, because we use it a lot in our daily lives so I need you to learn well and pay close attention so that you can solve them all . So I'll end the simple rule of three class here. Be sure to attend the compound rule of three class and don't forget to attend the classes on direct magnitudes, inversely proportional magnitudes, ratio, proportion, all that I've done, ok people?

I hope you understood, enjoyed the class, if you liked the class, subscribe to the Gis channel if you haven't subscribed yet and leave a thumbs up for me see you later!